Technical Field
[0001] The present invention relates to a novel infrared shielding sheet effectively absorbing
or reflecting infrared rays and having an excellent transparency and a low haze, and
also relates to a method for manufacturing the infrared shielding sheet and a use
thereof (e.g., for an interlayer film for glass, a laminated glass and a window member).
Background Art
[0002] Lately, in terms of energy saving or global environment issues, reducing burden of
air conditioning equipment is required. For example, in the fields of automobiles
and house construction, it is required that the temperature in a room or a cabin of
a vehicle is controlled by laying an infrared shielding material, which is capable
of blocking the infrared rays of sunlight, on window glasses.
[0003] Various materials capable of blocking the infrared rays are known. Patent Document
1 discloses a high insulating laminated glass for reflecting rays of light at a specific
wavelength in the infrared region. The insulating laminated glass is obtained by laminating,
between at least two opposite glass substrates: an infrared reflecting film made of
a multilayer film (dielectric multilayer film) where a high refractive index layer
and a low refractive index layer are alternately laminated; and a functional laminated
interlayer film (fine particle film) in which electroconductive ultrafine particles
(such as antimony-doped tin oxide) for blocking the infrared rays are uniformly dispersed.
In order to manufacture the high insulating laminated glass, the dielectric multilayer
film and the fine particle film are needed to be formed separately, which causes a
problem of manufacturing cost.
[0004] Patent Document 2 discloses a laminated glass for vehicle windows for reflecting
rays of light at a specific wavelength in the infrared region. The laminated glass
is obtained by laminating, between a first glass plate and a second glass plate: an
laminated film (dielectric multilayer film) where a high refractive index inorganic
material layer and a low refractive index inorganic material layer are alternately
laminated; and an interlayer film (fine particle film) in which infrared shielding
fine particles such as ITO (indium tin oxide) are dispersed and contained. In order
to manufacture the laminated glass for vehicle windows, the dielectric multilayer
film and the fine particle film are needed to be formed separately, which causes a
problem of manufacturing cost.
[0005] Patent Document 3 discloses an insulating glass obtained by alternately laminating,
on a glass substrate, a transparent conductive layer and a high refractive index layer.
The high refractive layer has a relatively high refractive index in the infrared region
compared with the refractive index of the transparent conductive layer. However, in
the insulating glass, the layer composed of only conductor is used as the low refractive
index layer in the infrared region. Thus, it cannot be used in any system of which
radio wave transmissibility is required so as to transmit and receive, for example,
signals of a mobile phone, a TV and a GPS (global positioning system) inside or outside
the room. Furthermore, for the insulating glass, vacuum facilities for sputtering
and the like are needed to form the layer composed of only the conductor, which causes
a problem of manufacturing cost.
Citation List
Patent Literature
Summery of Invention
Technical Problems
[0007] An object of the present invention is to provide a novel infrared shielding sheet
having remarkably improved transparency in the visible light region, radio wave transmissibility,
infrared shielding property, and manufacturing cost.
Solution to Problem
[0008] As a result of intensive studies to solve the above problems in the conventional
art, it is found that a novel infrared shielding sheet having transparency and radio
wave transmissibility can be realized, whose infrared shielding property and manufacturing
cost are also remarkably improved. The novel infrared shielding sheet includes a laminated
film formed by alternately laminating at least one high refractive index resin layer
containing fine particles and at least one low refractive index resin layer containing
fine particles, in which at least one of the at least one low refractive index resin
layer has a value of 0.1 or more that is obtained by subtracting a refractive index
at an arbitrary wavelength from 780 to 2500 nm from a refractive index at a wavelength
of 550 nm, and in which the at least one low refractive index resin layer has a refractive
index lower than a refractive index of the at least one high refractive index resin
layer at any wavelength in a range from 550 nm to the arbitrary wavelength inclusive.
Thus, the present invention is completed.
[0009] That is, the infrared shielding sheet of the present invention including a laminated
film formed by alternately laminating at least one high refractive index resin layer
containing fine particles and at least one low refractive index resin layer containing
fine particles is characterized in that: at least one of the at least one low refractive
index resin layers has a value of 0.1 or more that is obtained by subtracting a refractive
index at an arbitrary wavelength from 780 to 2500 nm from a refractive index at a
wavelength of 550 nm; and the at least one low refractive index resin layer has a
refractive index lower than a refractive index of the at least one high refractive
index resin layer at any wavelength in the range from 550 nm to the arbitrary wavelength
inclusive.
Advantageous Effects of Invention
[0010] The infrared shielding sheet of the present invention has a good absorption property
and reflection property in a wide infrared region and is excellent in radio wave transmissibility,
transparency, and manufacturing cost. Furthermore, the infrared shielding sheet of
the present invention has a low haze. Thus, it is possible to remarkably improve the
infrared shielding property. When the infrared shielding sheet of the present invention
is laid on window glasses of a house or a vehicle, both reduction effects of heating
cost in winter and temperature in summer can be improved.
Brief Description of Drawings
[0011]
[FIG. 1] FIG. 1 is a graph showing the transmittance and the reflectance of an infrared
shielding sheet according to Example 1 of the present invention plotted against wavelength.
[FIG. 2] FIG. 2 is a graph showing the refractive index and the reflectance of an
infrared shielding sheet according to Comparative Example 1 plotted against wavelength.
[FIG. 3] FIG. 3 is a graph showing the transmittance and the reflectance of an infrared
shielding sheet according to Example 10 of the present invention, as well as showing
energy of the sunlight reaching the surface of the earth plotted against wavelength.
[FIG. 4] FIG. 4 is a graph showing the refractive index and the reflectance of an
infrared shielding sheet according to Comparative Example 2 plotted against wavelength.
[FIG. 5] FIG. 5 is a cross-sectional view schematically showing an example of an interlayer
film for laminated glass according to an embodiment of the present invention.
[FIG. 6] FIG. 6 is a cross-sectional view schematically showing one aspect of a laminated
glass using the interlayer film for laminated glass according to FIG. 5.
[FIG. 7] FIG. 7 is a cross-sectional view schematically showing an infrared shielding
sheet according to one aspect of the present invention.
Description of Embodiments
[0012] The infrared shielding sheet of the present invention includes a laminated film formed
by alternately laminating at least one high refractive index resin layer containing
fine particles and at least one low refractive index resin layer containing fine particles.
At least one of the at least one low refractive index resin layer has a value of 0.1
or more that is obtained by subtracting a refractive index at an arbitrary wavelength
from 780 to 2500 nm from a refractive index at a wavelength of 550 nm. The at least
one low refractive index resin layer has a refractive index lower than a refractive
index of the at least one high refractive index resin layer at any wavelength in the
range from 550 nm to the arbitrary wavelength inclusive. With the above configuration,
since at least one of the at least one low refractive index resin layer has the value
of 0.1 or more that is obtained by subtracting the refractive index at an arbitrary
wavelength from 780 to 2500 nm from the refractive index at the wavelength of 550
nm, it is possible to reduce a difference in the refractive index between at least
one of the at least one low refractive index resin layer and the high refractive index
resin layer adjacent thereto at the wavelength of 550 nm, while increasing a difference
in the refractive index between at least one of the at least one low refractive index
resin layer and the high refractive index resin layer adjacent thereto at an arbitrary
wavelength from 780 to 2500 nm. As a result, it is possible to realize an infrared
shielding sheet having a good visible light transmittance and a good infrared shielding
property. Also, with the above configuration, since the high refractive index layer
containing the fine particles and the low refractive index layer containing the fine
particles are both resin layers, it is possible to manufacture the laminated film
easily by application method and the like, thereby to reduce the manufacturing cost.
Furthermore, with the above configuration, since the high refractive index layer containing
the fine particles and the low refractive index layer containing the fine particles
are both resin layers, it is possible to realize an infrared shielding sheet having
the radio wave transmissibility. Note that the term "infrared region" in the present
application documents means the wavelength region from 780 to 2500 nm.
[0013] All of the at least one low refractive index resin layer may have a value of 0.1
or more that is obtained by subtracting the refractive index at an arbitrary wavelength
from 780 to 1500 nm from the refractive index at the wavelength of 550 nm. Also, in
the infrared shielding sheet of the present invention, the high refractive index resin
layer may have a value of 0.1 or less that is obtained by subtracting the refractive
index at an arbitrary wavelength from 780 to 1500 nm from the refractive index at
the wavelength of 550 nm, and the low refractive index resin layer may have the value
of 0.1 or more that is obtained by subtracting the refractive index at an arbitrary
wavelength from 780 to 1500 nm from the refractive index at the wavelength of 550
nm. This makes it possible to reduce the difference in the refractive index between
the low refractive index resin layer and the high refractive index resin layer at
the wavelength of 550 nm, while further increasing the difference in the refractive
index between the low refractive index resin layer and the high refractive index resin
layer at an arbitrary wavelength from 780 to 1500 nm. As a result, it is possible
to realize an infrared shielding sheet having better infrared shielding property while
maintaining the good visible light transmittance.
[0014] Preferably, the infrared shielding sheet further includes a transparent support on
which the laminated film is formed.
[0015] As shown in FIG. 7, the infrared shielding sheet according to one aspect of the present
invention includes a laminated film 23 formed by alternately laminating a high refractive
index resin layer 21 containing fine particles and a low refractive index resin layer
22 containing fine particles on a transparent support 20. In the aspect shown in FIG.
7, the total number of the high refractive index resin layers 21 and the low refractive
index resin layers 22 is an even number (8), and the low refractive index resin layer
22 is the end layer on the side of transparent support 20 of the laminated film 23.
However, the total number of the high refractive index resin layers 21 and the low
refractive index resin layers 22 may be an odd number (e.g., 7), and the high refractive
index resin layer 21 may be the end layer on the side of the transparent support 20
of the laminated film 23.
[0016] Various resin films, glasses and the like can be used as the transparent support.
As the resin films, for example, the following can be used: a polyolefin film such
as a polyethylene film and a polypropylene film; a polyester film such as a polyethylene
terephthalate (hereinafter referred to as "PET") film, a polybutylene terephthalate
film and a polyethylene naphthalate (hereinafter referred to as "PEN") film; a polycarbonate
film; a polyvinyl chloride film; a cellulose triacetate film; a polyamide film; and
a polyimide film.
[0017] In the infrared shielding sheet including the laminated film formed by alternately
laminating the high refractive index resin layer and the low refractive index resin
layer, the difference in the refractive index between the high refractive index resin
layer and the low refractive index resin layer in the infrared region has an important
role as well as an absolute value of the refractive index of the high refractive index
resin layer, for determining the infrared reflecting function. That is, as the difference
in the refractive index increases, and as the absolute value of the refractive index
increases, the infrared reflecting function increases.
[0018] In the present invention, it is preferable that the difference in the refractive
index between at least two layers adjacent to each other (the high refractive index
resin layer and the low refractive index resin layer) is 0.1 or more at the wavelength
(the wavelength arbitrarily set out of the infrared region from 780 to 2500 nm) of
the infrared rays reflected by the laminated film. The above difference is more preferably
0.2 or more, still more preferably 0.3 or more, particularly preferably 0.35 or more.
[0019] When the difference in the refractive index of the two layers adjacent to each other
is less than 0.1 at the wavelength of the infrared rays reflected by the laminated
film, the number of layers should be increased to obtain a desirable infrared reflectance,
which is undesirable due to reduction in the visible light transmittance and increase
of the manufacturing cost.
[0020] Here, as shown in FIG. 3, there are some peaks of the energy in the infrared region
of the sunlight that reaches the surface of the earth. Therefore, when blocking the
infrared region of the sunlight is desired, it is important to block effectively the
above peaks of the energy. As a result of intensive studies, it is found that the
infrared region of the sunlight can be effectively blocked under the condition in
which the optical thickness of at least one of the at least one high refractive index
resin layer and the at least one low refractive index resin layer has the coefficient
of the quarter wave optical thickness (hereinafter referred to as "QWOT") of 1.5 or
more in an arbitrary wavelength from 780 to 2500 nm. Here, the coefficient of the
QWOT related to the optical thickness is set to 1 when the equation nd=λ/4 is satisfied,
where n represents the refractive index of the high refractive index resin layer or
the low refractive index resin layer, d represents the geometric thickness of the
high refractive index resin layer or the low refractive index resin layer, and λ represents
the infrared wavelength (the wavelength arbitrarily set out of the infrared region
from 780 to 2500 nm) reflected by the laminated film.
[0021] In the infrared shielding sheet of the present invention, it is preferable that the
low refractive index resin layer has the refractive index lower than the refractive
index of the high refractive index resin layer at an arbitrary wavelength from 780
to 2500 nm. Also, in the infrared shielding sheet of the present invention, it is
preferable that the low refractive index resin layer has the refractive index lower
than the refractive index of the high refractive index resin layer at an arbitrary
wavelength from 780 to 2500 nm, and furthermore that at least one of the at least
one high refractive index resin layer and/or at least one of the at least one low
refractive index resin layer have/has the coefficient of the QWOT of 1.5 or more related
to the optical thickness in an arbitrary wavelength from 780 to 2500 nm. This enables
the peaks of the energy of the infrared region of the sunlight to be effectively reflected,
thus the infrared rays can be efficiently blocked.
[0022] In the infrared shielding sheet having the above-described configuration, it is preferable
that at least one of the at least one high refractive index resin layer and the at
least one low refractive index resin layer, which are adjacent to the layer having
the coefficient of the QWOT of 1.5 or more related to the optical thickness at the
arbitrary wavelength, has the coefficient of the QWOT of 1 or more related to the
optical thickness at the arbitrary wavelength. This makes it possible to efficiently
block the infrared rays in the region of the infrared rays having the wavelengths
(e.g., in the range from 780 nm to less than 1000 nm) shorter than the arbitrary wavelength.
Also, it is preferable that the infrared shielding sheet having the above-described
configuration includes: at least one high refractive index resin layer having the
coefficient of the QWOT of 1 related to the optical thickness at the arbitrary wavelength;
and at least one low refractive index resin layer having the coefficient of the QWOT
of 1 related to the optical thickness at the arbitrary wavelength. This makes it possible
to efficiently block the infrared rays having wavelengths in the vicinity of the arbitrary
wavelength. Furthermore, in the infrared shielding sheet having the above-described
configuration, it is preferable that the arbitrary wavelength is from 780 to 1500
nm. This makes it possible to efficiently block the infrared rays.
[0023] Regarding the layers other than the layer(s) whose coefficient of the QWOT related
to the optical thickness is 1.5 or more out of the at least one high refractive index
resin layer and the at least one low refractive index resin layer, the infrared wavelength
λ thereof reflected by the laminated film is generally given by the equation (1) below:
where n
H and d
H represent, respectively, the refractive index and the geometric thickness of the
high refractive index resin layer, and n
L and d
L represent, respectively, the refractive index and the geometric thickness of the
low refractive index resin layer.
[0024] The optical thickness (product of the refractive index n
H and the geometric thickness d
H) of the high refractive index resin layer and the optical thickness (product of the
refractive index n
L and the geometric thickness d
L) of the low refractive index resin layer may be the same value that is the integral
multiple of λ/4. Specifically, the optical thickness of each of the high refractive
index resin layer and the low refractive index resin layer at the arbitrary wavelength
from 780 to 1500 nm (e.g., the optical thickness at the wavelength of 1200 nm) may
be in the range from 195 to 375 nm. This makes it possible to realize the infrared
shielding sheet having a good visible light transmittance and a good infrared shielding
property.
[0025] The infrared wavelength λ reflected by the laminated film may be in the range from
780 to 2500 nm, but more preferably, in the range from 780 to 1500 nm. When the infrared
wavelength λ reflected by the laminated film is less than 780 nm, the infrared wavelength
λ reflected by the laminated film is the wavelength in the visible light region. Thus,
it is undesirable due to reduction in the visible light transmittance of the infrared
shielding sheet. Also, when the infrared wavelength λ reflected by the laminated film
exceeds 1500 nm, absorption by the fine particles contained in the low refractive
index resin layer occurs, thus it is undesirable due to degradation of the infrared
shielding effect.
[0026] In the infrared shielding sheet of the present invention, the total number of the
at least one high refractive index resin layer and the at least one low refractive
index resin layer (i.e., the number of the layers of the multilayer film) is preferably
3 or more, more preferably 4 or more. When the total number of the at least one high
refractive index resin layer and the at least one low refractive index resin layer
is less than 3, the infrared reflecting function is insufficient. When the total number
of the at least one high refractive index resin layer and the at least one low refractive
index resin layer is 3 or more, the total number of the at least one high refractive
index resin layer and the at least one low refractive index resin layer is more preferably
in the range from 3 to 30, and still more preferably in the range from 3 to 20, particularly
preferably in the range from 3 to 15. Also, when the total number of the at least
one high refractive index resin layer and the at least one low refractive index resin
layer is 4 or more, the total number of the at least one high refractive index resin
layer and the at least one low refractive index resin layer is more preferably in
the range from 4 to 30, and still more preferably in the range from 4 to 20, particularly
preferably in the range from 4 to 15. When the total number of the at least one high
refractive index resin layer and the at least one low refractive index resin layer
exceeds 30, it is undesirable due to increase of the manufacturing cost, reduction
in the visible light transmittance, reduction in the durability and curl of the infrared
shielding sheet caused by increase of stress of the multilayer film composed of the
high refractive index resin layers and the low refractive index resin layers.
[0027] Regarding the optical performance, the infrared shielding sheet having a high visible
light transmittance and a low total solar transmittance is ideal. However, in general,
the visible light transmittance bears a proportional relationship with the solar transmittance.
Thus, the optical performance is determined depending on which transmittance is considered
to be important. Upon various studies, when the infrared shielding sheet of the present
invention is laid on window glasses of a house or a vehicle, the visible light transmittance
of the infrared shielding sheet of the present invention is preferably 50% or more,
more preferably 70% or more, in order to minimize increase of the lighting cost inside
the house or the vehicle and the heating cost in winter. The total solar transmittance
of the infrared shielding sheet is preferably 80% or less, more preferably 75% or
less, in order to effectively block the infrared rays. Furthermore, the haze of the
infrared shielding sheet should not impair the transparency of the infrared shielding
sheet, thus the haze is preferably 8% or less, more preferably 3% or less, still more
preferably 1% or less.
[0028] When manufacturing the multilayer film using the difference in the refractive index
between the high refractive index layer and the low refractive index layer by alternately
laminating the high refractive index layer and the low refractive index layer by applicationmethod,
the conventional art allows the high refractive index resin layer to contain dielectric
fine particles (titanium oxide fine particles and the like) having a high refractive
index, and the low refractive index resin layer to contain dielectric fine particles
(silica fine particles and the like) having a low refractive index (for example, see
Patent Document
JP 2012-093481 A). The refractive index of the dielectric fine particles is substantially fixed from
the visible light region to the infrared region, and the refractive index of the low
refractive index resin layer is substantially fixed from the visible light region
to the infrared region.
[0029] However, upon various studies, the low refractive index resin layer containing fine
particles was found, which has a value of 0.1 or more that is obtained by subtracting
the refractive index at an arbitrary wavelength from 780 to 2500 nm (particularly
from 780 to 1500 nm) in the infrared region from the refractive index at the wavelength
of 550 nm in the visible light region. Furthermore, since the low refractive index
resin layer containing the fine particles also has the infrared absorbing function,
it is found that the light in the infrared region can be blocked more efficiently
than the conventional art by combining the low refractive index resin layer containing
the fine particles with the high refractive index resin layer containing the fine
particles (in particular, the high refractive index resin layer having a value of
0.1 or less that is obtained by subtracting the refractive index at an arbitrary wavelength
from 780 to 1500 nm from the refractive index at the wavelength of 550 nm, e.g., the
high refractive index resin layer containing the dielectric fine particles such as
titanium oxide that is used in the conventional art).
[0030] For satisfying the above-described condition, the fine particles hardly absorbing
the light in the visible light region and having a high refractive index in the infrared
region is suitable for the fine particles contained in the high refractive index resin
layer. Examples of the above fine particles include dielectric fine particles composed
of the dielectrics such as titanium oxide, zirconium oxide, hafnium oxide, tantalum
oxide, tungsten oxide, niobium oxide, cerium oxide, lead oxide, zinc oxide, diamond
and the like. In particular, at least one kind of the dielectric fine particles selected
from titanium oxide, zirconium oxide, zinc oxide and diamond are preferable. Other
than the dielectric fine particles composed of the dielectrics as shown above, boride
fine particles and nitride fine particles are exemplified as the electrically conductive
metal oxide fine particles having high refractive index in the infrared region and
having the infrared absorbing function. As the boride fine particles and the nitride
fine particles, in particular, lanthanum hexaboride fine particles and titanium nitride
fine particles are preferable. At least one layer of the at least one high refractive
index resin layer preferably contains at least one kind of fine particles selected
from the group consisting of titanium oxide, zirconium oxide, hafnium oxide, tantalum
oxide, tungsten oxide, niobium oxide, cerium oxide, lead oxide, zinc oxide, diamond,
boride and nitride.
[0031] The fine particles having a high refractive index in the infrared region may be used
singularly or used in combination of two kinds or more. Furthermore, the different
fine particles may be used relative to the respective high refractive index resin
layers in the laminated film.
[0032] It is preferable that the fine particles contained in at least one of the at least
one low refractive index resin layer hardly absorb the light in the visible light
region, successfully absorb the light in the infrared region, and furthermore have
a relatively low refractive index compared with the refractive index of the fine particles
contained in the high refractive index resin layer. Examples of the above fine particles
include electrically conductive metal oxide fine particles that have a plasma wavelength
in the infrared region. As the metal oxide fine particles, in particular, metal oxide
fine particles of tin oxide, indium oxide, zinc oxide, tungsten oxide, chromium oxide,
molybdenum oxide and the like are exemplified. Out of the above, at least one kind
of fine particles selected from the group consisting of at least one of tin oxide,
indium oxide, zinc oxide and tungsten oxide is preferable because such fine particles
hardly absorb the light in the visible light region. In particular, the indium oxide
fine particles are still more preferable.
[0033] Also, in order to improve the electrical conduction property of the metal oxide fine
particles, it is preferable that the metal oxide fine particles are doped with a third
component (third element, i.e., dopant). As the dopant with which the tin oxide fine
particles are doped, antimony (Sb), vanadium (V), niobium (Nb), tantalum (Ta) and
the like are exemplified. As the dopant with which the indium oxide fine particles
are doped, zinc (Zn), aluminum (Al), tin (Sn), antimony, gallium (Ga), germanium (Ge)
and the like are exemplified. As the dopant with which the zinc oxide fine particles
are doped, aluminum, gallium, indium (In), tin, antimony, niobium and the like are
exemplified. As the dopant with which the tungsten oxide fine particles are doped,
cesium (Cs), rubidium (Rb), potassium (K), thallium (Tl), indium, barium (Ba), lithium
(Li), calcium (Ca), strontium (Sr), iron (Fe), tin, aluminum, copper (Cu) and the
like are exemplified. In order to improve the electrical conduction property of the
metal oxide fine particles, it is also preferable that the third component is replaced
by an oxygen defect. That is, the metal oxide fine particles may have the oxygen defect.
Examples of the metal oxide fine particles made of tungsten oxide fine particles having
the oxygen defect include oxygen defect tungsten oxide particles (oxygen-deficient
tungsten oxide particles) that are represented by the composition formula of WOx (where
2.45 ≤ x ≤2.999) and the like. Among the metal oxide fine particles that are doped
with the third component or have the oxygen defect, it is preferable to use at least
one kind of fine particles selected from the group consisting of antimony-doped tin
oxide (ATO), tin-doped indium oxide (hereinafter occasionally referred to as "ITO"),
gallium-doped zinc oxide (GZO), oxygen-deficient tungsten oxide, and cesium-doped
tungsten oxide, and it is more preferable to use tin-doped indium oxide.
[0034] Also, when compressed under the pressure of 60 MPa, the above-described metal oxide
fine particles preferably have the powder resistivity of 100Ω · cm or less, more preferably
have the powder resistivity of 10Ω · cm or less, still more preferably have the powder
resistivity of 1Ω · cm. In case of using the fine particles having the powder resistivity
higher than 100Ω · cm when compressed under the pressure of 60 MPa, absorption due
to plasma resonance of the fine particles occurs at the wavelength of more than 2500
nm, thus reducing the infrared shielding effect. Regarding the method for measuring
the powder resistivity, it is preferable to use the powder resistivity measurement
system MCP-PD51 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.), however,
the method is not limited thereto.
[0035] Also, when at least one of the at least one low refractive index resin layer contains
non-hollow fine particles (solid fine particles), in particular, at least one kind
of non-hollow fine particles selected from the group consisting of tin oxide, indium
oxide, zinc oxide and tungsten oxide, at least one of the at least one low refractive
index resin layer (which may be the same as or different from the layer containing
the non-hollow fine particles) preferably contains hollow fine particles, more preferably
contains hollow fine particles having the low refractive index (especially, the hollow
fine particles having the refractive index lower than the refractive index of the
non-hollow fine particles). This makes it possible to further improve the infrared
shielding effect of the infrared shielding sheet.
[0036] As the hollow fine particles, it is possible to use known hollow fine particles such
as hollow silica fine particles and hollow acrylic beads (hollow acrylic resin fine
particles). As the non-hollow fine particles, it is preferable to use at least one
kind of non-hollow fine particles selected from the group consisting of at least one
of tin oxide, indium oxide, zinc oxide and tungsten oxide, and it is more preferable
to use at least one kind of non-hollow fine particles selected from the group consisting
of antimony-doped tin oxide, ITO, gallium-doped zinc oxide, oxygen-deficient tungsten
oxide, and cesium-doped tungsten oxide.
[0037] It is preferable that the hollow fine particles have the porosity from 10 to 90 vol%.
The hollow fine particles having the porosity less than 10 vol% reduce an effect decreasing
the refractive index of the fine particles obtained by the hollows in the hollow fine
particles, which also reduces an effect obtained by use of the hollow fine particles
in the low refractive index resin layer. If the hollow fine particles have the porosity
of more than 90 vol%, the mechanical strength of the hollow fine particles is decreased,
which leads to an unfavorable result in which the hollow fine particles cannot maintain
the hollows.
[0038] When the hollow fine particles are combined with the non-hollow fine particles such
as the metal oxide non-hollow fine particles so as to be the fine particles contained
in the low refractive index resin layer, the ratio of the non-hollow fine particles
the fine particles contained in the low refractive index resin layer is preferably
from 10 to 90 wt%, more preferably from 20 to 90 wt%. If the ratio of the non-hollow
fine particles is less than 10 wt%, it is undesirable due to insufficient infrared
absorbing function obtained by the non-hollow fine particles. Also, if the ratio of
the non-hollow fine particles is more than 90 wt%, it is undesirable due to decrease
of the ratio of the hollow fine particles.
[0039] When at least one of the at least one low refractive index resin layer contains the
above-described electrically conductive metal oxide fine particles (hereinafter referred
to as "electrically conductive fine particles", which are in particular at least one
kind of fine particles selected from the group consisting of tin oxide, indium oxide,
zinc oxide and tungsten oxide), at least one of the at least one low refractive index
resin layer (which may be the same as or different from the layer containing the electrically
conductive metal oxide fine particles) can contain dielectric fine particles having
the low refractive index. As the dielectric fine particles, it is possible to use
silica fine particles, magnesium fluoride fine particles and the like. Furthermore,
as the dielectric fine particles, it is possible to use hollow dielectric fine particles.
Examples of the hollow dielectric fine particles include the hollow dielectric fine
particles such as hollow silica fine particles and hollow acrylic beads. When at least
one of the at least one low refractive index resin layer contains the electrically
conductive metal oxide fine particles (in particular, at least one kind of fine particles
selected from the group consisting of tin oxide, indium oxide, zinc oxide and tungsten
oxide), and in addition, when at least one of the at least one low refractive index
resin layer (which may be the same as or different from the layer containing the electrically
conductive metal oxide fine particles) contains the silica fine particles, in particular
the hollow silica fine particles, the refractive index of the low refractive index
resin layer is decreased, thus the infrared rays can be further effectively blocked.
[0040] When the electrically conductive fine particles are combined with the dielectric
fine particles (in particular, the hollow dielectric fine particles) so as to be contained
in the total of the at least one low refractive index resin layer, the ratio of the
electrically conductive fine particles in the fine particles contained in the total
of the at least one low refractive index resin layer is preferably from 10 to 90 wt%,
more preferably from 20 to 90 wt%. If the ratio of the electrically conductive fine
particles is less than 10 wt%, it is undesirable due to insufficient infrared absorbing
function obtained by the metal oxide. Also, if the ratio of the electrically conductive
fine particles is more than 90 wt%, it is undesirable due to decrease of the ratio
of the dielectric fine particles (in particular, the hollow dielectric fine particles).
[0041] The fine particles (the electrically conductive fine particles, the dielectric fine
particles, the hollow fine particles and the like) for the of the at least one low
refractive index resin layer may be used singularly or used in combination of two
kinds or more. When two or more kinds of fine particles are contained in the at least
one low refractive index resin layer, the different kinds of fine particles may be
contained in the respective low refractive index resin layers. Also, the different
kinds of fine particles may be contained in the same low refractive index resin layer.
[0042] Furthermore, in the infrared shielding sheet of the present invention, the fine particles
contained in the at least one high refractive index resin layer and the at least one
low refractive index resin layer have preferably the average primary particle size
or the average dispersed particle size of 300 nm or less, more preferably the average
primary particle size or the average dispersed particle size from 1 nm to 200 nm.
If the average primary particle size or the average dispersed particle size of the
fine particles exceeds 300 nm, the infrared shielding sheet has a high haze, which
results in a reduced visibility through the infrared shielding sheet. Note that the
term "the average primary particle size of the fine particles" in the present specification
means the average particle size of the fine particles before dispersion, and the term
"the average dispersed particle size of the fine particles" means the average particle
size of the fine particles in dispersion after the dispersion step. The average primary
particle size is calculated based on the specific surface area measured by the BET
(Brunauer-Emmett-Teller) method. The particle size distribution measurement apparatus
for measuring the average dispersed particle size is not particularly limited, however,
it is preferable to use "Nanotrac UPA-EX150" (manufactured by NIKKISO CO., LTD).
[0043] In order to satisfy the infrared shielding property, the smoothness, the low haze
and the radio wave transmissibility of the infrared shielding sheet, it is important
to adequately disperse the fine particles contained in the at least one high refractive
index resin layer and the at least one low refractive index resin layer. In order
to disperse the fine particles, the methods using the following are desirable: a sand
mill, an attritor, a ball mill, a homogenizer, a roll mill, a bead mill and the like.
Above all, the method using the bead mill is preferable. When the bead mill is used,
preferably the bead mill has the peripheral speed from 3 to 10m/s. If the peripheral
speed of the bead mill is less than 3m/s, the fine particles cannot be sufficiently
dispersed. If the peripheral speed of the bead mill is more than 10m/s, the surface
of the fine particles (especially the electrically conductive fine particles) contained
in particular in the at least one low refractive index resin layer is scratched, thereby
the infrared absorbing function is reduced. The appropriate range of the dispersion
energy slightly differs depending on, for example, the apparatus for dispersion, resin
binders contained in the at least one high refractive index resin layer and the at
least one low refractive index resin layer and the concentration of the fine particles
during dispersion. However, it is preferable to disperse the fine particles with a
relatively low dispersion energy. Furthermore, if coarse particles remain after the
dispersion of the fine particles, it is preferable that the coarse particles are removed
by further treatments such as filtration and centrifugation.
[0044] The high refractive index resin layer and the low refractive index resin layer can
be formed by: applying a dispersion liquid, which is obtained by dissolving a resin
binder and dispersing the fine particles in a solvent, to a surface of a body such
as the transparent support; and then vaporizing the solvent. The solvent used for
dispersion of the fine particles in the dispersion liquid is not particularly limited.
For example, it is possible to use water, an organic solvent, or a mixture of water
and an organic solvent. Examples of the above organic solvents include: a hydrocarbon
solvent (toluene, xylene, n-hexane, cyclohexane, n-heptane and the like); an alcohol
solvent (methanol, ethanol, isopropyl alcohol, butanol, t-butanol, benzyl alcohol
and the like); a ketone solvent (acetone, methyl ethyl ketone, methyl isobutyl ketone,
diisobutyl ketone, cyclohexanone, acetylacetone and the like); an ester solvent (ethyl
acetate, methyl acetate, butyl acetate, cellosolve acetate, amyl acetate and the like);
an ether solvent (isopropyl ether, 1,4-dioxane and the like); a glycol solvent (ethylene
glycol, diethylene glycol, triethylene glycol, propylene glycol and the like); a glycol
ether solvent (methyl cellosolve, butyl cellosolve, diethylene glycol monomethyl ether,
propylene glycol monomethyl ether and the like); a glycol ester solvent (ethylene
glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene
glycol monoethyl ether acetate and the like); a glyme solvent (monoglyme, diglyme
and the like); a halogen solvent (dichloromethane, chloroform and the like); an amide
solvent (N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone and
the like); pyridine; tetrahydrofuran; sulfolane; acetonitrile; and dimethyl sulfoxide.
The solvent used for dispersion is preferably at least one kind of the solvents selected
from the group consisting of the water, the ketone solvent, the alcohol solvent, the
amide solvent and the hydrocarbon solvent, and more preferably, at least one of the
solvents selected from the group consisting of toluene, methyl ethyl ketone, methyl
isobutyl ketone and acetylacetone.
[0045] When dispersing the fine particles in the solvent, a dispersant may be added to the
solvent. Representative dispersants are the following: a low molecular weight anionic
compound such as fatty acid salt (soap), α-sulfo fatty acid ester salt (MES), alkyl
benzene sulfonate (ABS), linear alkyl benzene sulfonate (LAS), alkyl sulfate (AS),
alkyl ether sulfate salt (AES) and alkyl sulfate triethanol; a low molecular weight
nonionic compound such as fatty acid ethanolamide, polyoxyethylene alkyl ether (AE),
polyoxyethylene alkyl phenyl ether (APE), sorbitol and sorbitane; a low molecular
weight cationic compound such as alkyltrimethylammonium salt, dialkyldimethylammonium
chloride and alkylpyridinium chloride; a low molecular weight zwitterion compound
such as alkylcarboxybetaine, sulfobetaine and lecithin; a high molecular weight aqueous
dispersant represented by formaldehyde condensate of naphthalenesulfonate, polystyrenesulfonate,
polyacrylate salt, copolymer salt of vinyl compound and calboxylic acid monomer, carboxymethyl
cellulose, polyvinyl alcohol and the like; a high molecular weight non-aqueous dispersant
such as polyacrylic acid partial alkyl ester and polyalkylenepolyamine; and a high
molecular weight cationic dispersant such as polyethyleneimine and aminoalkyl methacrylate
copolymer. However, any dispersant having a configuration other than the dispersants
stated above may be used provided that it could be suitably applied to the fine particles
used in the present invention.
[0046] As specific trade names of the above dispersants added to the solvent, for example,
the following are known: FLOWLEN™ DOPA-15B and FLOWLEN™ DOPA-17 (both manufactured
by Kyoeisha Chemical Co., Ltd.); Solplus™ AX5, Solplus™ TX5, Solsperse™ 9000, Solsperse™
12000, Solsperse™ 17000, Solsperse™ 20000, Solsperse™ 21000, Solsperse™ 24000, Solsperse™
26000, Solsperse™ 27000, Solsperse™ 28000, Solsperse™ 32000, Solsperse™ 35100, Solsperse™
54000 and Solthix™ 250 (all manufactured by Lubrizol Japan Limited); EFKA® 4008, EFKA®
4009, EFKA® 4010, EFKA® 4015, EFKA® 4046 , EFKA® 4047, EFKA® 4060, EFKA® 4080, EFKA®
7462, EFKA® 4020, EFKA® 4050, EFKA® 4055, EFKA® 4400, EFKA® 4401, EFKA® 4402, EFKA®
4403, EFKA® 4300, EFKA® 4320, EFKA® 4330, EFKA® 4340, EFKA® 6220, EFKA® 6225, EFKA®
6700, EFKA® 6780, EFKA® 6782 and EFKA® 8503 (all manufactured by BASF Japan Ltd.);
AJISPER® PA111 , AJISPER® PB711, AJISPER® PB821, AJISPER® PB822, AJISPER® PN411 and
Famex L-12 (all manufactured by Ajinomoto Fine-Techno Co., Ltd.); TEXAPHOR®-UV21 and
TEXAPHOR®-UV61 (both manufactured by BASF Japan Ltd.); DISPERBYK®-101, DISPERBYK®-102,
DISPERBYK®-106, DISPERBYK®-108, DISPERBYK®-111, DISPERBYK®-116, DISPERBYK®-130, DISPERBYK®-140,
DISPERBYK®-142, DISPERBYK®-145, DISPERBYK®-161, DISPERBYK®-162, DISPERBYK®-163, DISPERBY
K®-164, DISPERBY K®-166, DISPERBYK®-167, DISPERBYK®-168, DISPERBYK©-170, DISPERBYK®-171,
DISPERBYK®-174, DISPERBYK®-180, DISPERBYK®-182, DISPERBYK®-192, DISPERBYK®-193, DISPERBYK®-2000,
DISPERBYK®-2001, DISPERBYK®-2020, DISPERBYK®-2025, DISPERBYK®-2050, DISPERBYK®-2070,
DISPERBYK®-2155, DISPERBYK®-2164, BYK® 220S, BYK® 300, BYK® 306, BYK® 320, BYK® 322,
BYK® 325, BYK® 330, BYK® 340, BYK® 350, BYK® 377, BYK® 378, BYK® 380N, BYK® 410, BYK®
425 and BYK® 430 (all manufactured by BYK Japan KK); DISPARLON® 1751N, DISPARLON®
1831, DISPARLON® 1850, DISPARLON® 1860, DISPARLON® 1934, DISPARLON® DA-400N, DISPARLON®
DA-703-50, DISPARLON® DA-725, DISPARLON® DA-705, DISPARLON® DA-7301, DISPARLON® DN-900,
DISPARLON® NS-5210, DISPARLON® NVI-8514L, HIPLAAD® ED-152, HIPLAAD® ED-216, HIPLAAD®
ED-251 and HIPLAAD® ED-360 (all manufactured by Kusumoto Chemicals, Ltd.); FTX-207S,
FTX-212P, FTX-220P, FTX-220S, FTX-228P, FTX-710LL, FTX-750LL, FTERGENT® 212P, FTERGENT®
220P, FTERGENT® 222F, FTERGENT® 228P, FTERGENT® 245F, FTERGENT® 245P, FTERGENT® 250,
FTERGENT® 251, FTERGENT® 710FM, FTERGENT® 730FM, FTERGENT® 730LL, FTERGENT® 730LS,
FTERGENT® 750DM and FTERGENT® 750FM (all manufactured by Neos Company Limited); AS-1100,
AS-1800 and AS-2000 (all manufactured by Toagosei Company, Limited); KAOCER® 2000,
KAOCER® 2100, KDH-154, MX-2045L, HOMOGENOL® L-18, HOMOGENOL® L-95, RHEODOL® SP-010V,
RHEODOL® SP-030V, RHEODOL® SP-L10 and RHEODOL® SP-P10 (all manufactured by Kao Corporation);
EPAN U103, SHALLOL® DC902B, NOIGEN® EA-167, PLYSURF® A219B and PLYSURF® AL (all manufactured
by Daiichi Kogyo Seiyaku Co., Ltd,); MEGAFAC® F-477, MEGAFAC® 480SF and MEGAFAC® F-482
(all manufactured by DIC Corporation); SILFACE® SAG 503A and Dynol 604 (both manufactured
by Nissin Chemical Industry Co., Ltd.); SN-SPERSE 2180, SN-SPERSE 2190 and SN-LEVELER
S-906 (all manufactured by SAN NOPCO LIMITED); and S-386 and S-420 (both manufactured
by AGC Seimi Chemical Co., Ltd.).
[0047] In the high refractive index resin layer and the low refractive index resin layer,
the fine particles are dispersed in the resin binder. The resin binder is not particularly
limited provided that it can maintain the fine particles dispersed therein. Examples
of the resin binder include a thermoplastic resin, thermosetting resin and photocurable
resin.
[0048] Examples of the thermoplastic resin include, but are not limited to: a high density
polyethylene resin; a (non-linear) low density polyethylene resin; a linear low density
polyethylene resin; an ultra low density polyethylene resin; a polypropylene resin;
a polybutadiene resin; a cyclic olefin resin; a polymethylpentene resin; a polystyrene
resin; an ethylene-vinylacetate copolymer; an ionomer resin; an ethylene vinyl alcohol
copolymer resin; an ethylene-ethyl acrylate copolymer; a styrene-acrylonitrile resin;
an acrylonitrile-chlorinated polystyrene-styrene copolymer resin; an acrylonitrile-acrylic
rubber-styrene copolymer resin; an acrylonitrile-butadienestyrene copolymer resin;
an acrylonitrile-EPDM (ethylene-propylene-diene monomer)-styrene copolymer resin;
a silicone rubber-acrylonitrile-styrene copolymer resin; a cellulose acetate butyrate
resin; a cellulose acetate resin; an acrylic resin (methacrylic resin); an ethylene
- methyl methacrylate copolymer; an ethylene-ethyl acrylate copolymer; a vinyl chloride
resin; a chlorinated polyethylene resin; a polytetrafluoroethylene resin; a tetrafluoroethylene-hexafluoropropylene
copolymer resin; a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer resin;
a tetrafluoroethylene-ethylene copolymer resin; a polytrifluorochloroethylene resin;
polyvinylidene fluoride resin; a nylon 4,6; a nylon 6; a nylon 6,6; a nylon 6,10;
a nylon 6,12; a nylon 12; a nylon 6T; a nylon 9T; an aromatic nylon resin; a polyacetal
resin; an ultra high molecular weight polyethylene resin; a polybutylene terephthalate
resin; a PET resin; a polyethylene naphthalate resin; an amorphous copolyester resin;
a polycarbonate resin; a modified polyphenylene ether resin; a thermoplastic polyurethane
elastomer; a polyphenylene sulfide resin; a polyether ether ketone resin; a liquid
crystal polymer; a polyfluoroalkoxy resin; polyether imide resin; a polysulphone resin;
polyketone resin; a thermoplastic polyimide resin; a polyamide imide resin; a polyarylate
resin; a polyether sulfone resin; a biodegradable resin and a biomass resin. Also,
the thermoplastic resin may be a combination of two or more of the above resins.
[0049] The thermosetting resin is not particularly limited provided that it is a compound
having a functional group that is capable of being cured by heating. Examples of such
a thermosetting resin include a curable compound having a cyclic ether group such
as an epoxy group and an oxetanyl group. The photocurable resin is not particularly
limited provided that it is a compound having a functional group that is capable of
being cured by photoirradiation. Examples of such a photocurable resin include a resin
having an unsaturated double bond-containing group such as a vinyl group, a vinyl
ether group, an allyl group, a maleimide group and a (meth) acrylic group.
[0050] The curable compound having the cyclic ether group is not particularly limited. Examples
of the curable compound include an epoxy resin other than the alicyclic epoxy resin,
an alicyclic epoxy resin, an oxetane resin and a furan resin. Among the above resins,
the epoxy resin other than the alicyclic epoxy resin, the alicyclic epoxy resin and
the oxetane resin are suitable in consideration of the reaction rate and the versability.
The epoxy resin other than the alicyclic epoxy resin is not particularly limited.
Examples of the epoxy resin other than the alicyclic epoxy resin include: a novolak
type epoxy resin such as a phenol novolak type epoxy resin, a cresol novolak type
epoxy resin, a biphenyl novolak type epoxy resin, trisphenol novolak type epoxy resin
and a dicyclopentadiene novolak type epoxy resin; and a bisphenol type epoxy resin
such as a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a 2,2'-diallyl
bisphenol A type epoxy resin, a hydrogenated bisphenol type epoxy resin and a polyoxypropylene
bisphenol A type epoxy resin. As the epoxy resin other than the alicyclic epoxy resin,
a glycidylamine type epoxy resin can be also exemplified.
[0051] Examples of commercial products of the above epoxy resins include the phenol novolak
type epoxy resins such as EPICLON® N-740, EPICLON® N-770 and EPLCLON® N-775 (all manufactured
by DIC Corporation), and EPIKOTE® 152 and EPIKOTE® 154 (both manufactured by Mitsubishi
Chemical Corporation); the cresol novolak type epoxy resins such as EPICLON® N-660,
EPICLON® N-665, EPICLON® N-670, EPICLON® N-673, EPICLON® N-680, EPICLON® N-695, EPICLON®
N-665-EXP and EPICLON® N-672-EXP (all manufactured by DIC Corporation); the biphenyl
novolak type epoxy resins such as NC-3000P (manufactured by Nippon Kayaku Co., Ltd.);
the trisphenol novolak type epoxy resins such as EP 1032S50 and EP 1032H60 (both manufactured
by Mitsubishi Chemical Corporation); the dicyclopentadiene novolak type epoxy resins
such as XD-1000-L (manufactured by Nippon Kayaku Co., Ltd.) and EPICLON® HP-7200 (manufactured
by DIC Corporation); the bisphenol A type epoxy compounds such as EPIKOTE® 828, EPIKOTE®
834, EPIKOTE® 1001 and EPIKOTE® 1004 (all manufactured by Japan Epoxy Resins Co.,
Ltd), and EPICLON® 850, EPICLON® 860 and EPICLON® 4055 (all manufactured by DIC Corporation);
the bisphenol F type epoxy resins such as EPIKOTE® 807 (manufactured by Mitsubishi
Chemical Corporation) and EPICLON® 830 (manufactured by DIC Corporation); the 2,2'-diallyl
bisphenol A type epoxy resins such as RE-810NM (manufactured by Nippon Kayaku Co.,
Ltd.); the hydrogenerated bisphenol type epoxy resins such as ST-5080 (manufactured
by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD.); and the polyoxypropylene bisphenol
A type epoxy resins such as EP-4000 and EP-4005 (both manufactured by ADEKA CORPORATION).
[0052] The alicyclic epoxy resin is not particularly limited. Examples of the alicyclic
epoxy resin include CELOXIDE® 2021, CELOXIDE® 2080 and CELOXIDE® 3000 (all manufactured
by DAICEL-ALLNEX LTD.). Examples of the commercial products of the oxetane resin include
ETERNACOLL® EHO, ETERNACOLL® OXBP, ETERNACOLL® OXTP and ETERNACOLL® OXMA (all manufactured
by Ube Industries, Ltd.). The curable compound having the cyclic ether group may be
used singularly or may be used in combination of two kinds or more.
[0053] The photocurable resin having the unsaturated double bond-containing group is not
particularly limited. Examples of such a photocurable resin include a resin having
a group such as a vinyl group, a vinyl ether group, an allyl group, a maleimide group
and a (meth)acrylic group. Among the resins having the above groups, a resin having
a (meth)acrylic group is preferable in consideration of the reaction rate and the
versability. Note that in this Specification, the (meth)acrylic group means an acrylic
group or a methacrylic group.
[0054] Examples of the resin having the (meth)acrylic group include: 2-hydroxyethyl (meth)acrylate;
2-hydroxypropyl (meth)acrylate; 1,4-butanediol mono(meth)acrylate; carbitol (meth)acrylate;
acryloyl morpholine; half ester which is a reactant of hydroxyl group-containing (meth)acrylate
and polycarboxylic acid anhydride; polyethylene glycol di(meth)acrylate; tripropylene
glycol di(meth)acrylate; trimethylolpropane tri(meth)acrylate; trimethylolpropane
polyethoxy tri(meth)acrylate; glycerin polypropoxy tri(meth)acrylate; di(meth)acrylate
of ε-caprolactone adduct of neopentyl glycol hydroxypivalate (e.g., KAYARAD® HX-220
and KAYARAD® HX-620 manufactured by Nippon Kayaku Co., Ltd.); pentaerythritol tetra(meth)acrylate;
poly(meth)acrylate which is a reactant of dipentaerythritol and ε-caprolactone; dipentaerythritol
poly(meth)acrylate (e.g., KAYARAD® DPHA manufactured by Nippon Kayaku Co., Ltd.);
epoxy (meth)acrylate which is a reactant of (meth)acrylic acid and a monoglycidyl
compound or a polyglycidyl compound. Note that in this Specification, the (meth)acrylate
means acrylate or methacrylate and the (meth)acrylic acid means acrylic acid or methacrylic
acid.
[0055] The glycidyl compound (i.e., the monoglycidyl compound or the polyglycidyl compound)
used for epoxy (meth)acrylate which is a reactant of (meth)acrylic acid and the monoglycidyl
compound or the polyglycidyl compound is not particularly limited. Examples of the
above glycidyl compound include glycidyl-etherified products of polyphenols such as:
bisphenol A; bisphenol F; bisphenol S; 4,4'-biphenol; tetramethyl bisphenol A; dimethyl
bisphenol A; tetramethyl bisphenol F; dimethyl bisphenol F; tetramethyl bisphenol
S; dimethyl bisphenol S; tetramethyl-4,4'-biphenol; dimethyl-4,4'-biphenol; 1-(4-hydroxyphenyl)-2-[4-(1,1-bis(4-hydroxyphenyl)ethyl)phenyl]propane;
2,2'-methylenebis(4-methyl-6-tert-butylphenol); 4,4'-butylidene-bis(3-methyl-6-tert-butylphenol);
tris(hydroxyphenyl)methane; resorcinol; hydroquinone; pyrogallol; phenols having a
diisopropylidene skeleton; phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenyl
fluorene; phenolated polybutadiene; brominated bisphenol A; brominated bisphenol F;
brominated bisphenol S; brominated phenol novolak; brominated cresol novolak; chlorinated
bisphenol S; and chlorinated bisphenol A.
[0056] The epoxy (meth)acrylate which is a reactant of (meth)acrylic acid and the monoglycidyl
compound or the polyglycidyl compound can be obtained by performing an esterification
reaction of an epoxy group (glycidyl group) of the monoglycidyl compound or the polyglycidyl
compound with an equivalent of (meth)acrylic acid. Such a synthesis reaction can be
carried out using the generally known method. For example, to resorcin diglycidyl
ether, an equivalent of (meth)acrylic acid is added along with a catalyst (e.g., benzyldimethylamine,
triethylamine, benzyltrimethylammonium chloride, triphenylphosphine and triphenylstibine)
and a polymerization inhibitor (e.g., methoquinone, hydroquinone, methylhydroquinone,
phenothiazine and dibutylhydroxytoluene). Thus, the esterification reaction is performed
at 80 to 110°C. The obtained (meth)acrylated resorcin diglycidyl ether is a resin
having a radical polymerizable (meth)acryloyl group. Note that in this Specification,
(meth)acrylated means acrylated or methacrylated and the (meth)acryloyl group means
an acryloyl group or a methacryloyl group.
[0057] To the resin binder contained in the infrared shielding sheet of the present invention,
when it is a photocurable resin, a photopolymerization initiator can be added, if
necessary. When the resin binder is a thermosetting resin, it is possible, if necessary,
to add a hardener to the resin binder. The above photopolymerization initiator is
not particularly limited provided that it is to polymerize an unsaturated double bond,
an epoxy group, or the like in the photocurable resin by the photoirradiation. Examples
of the photopolymerization initiator include a cationic polymerization type photopolymerization
initiator and a radical polymerization type photopolymerization initiator. Also, it
is possible to use photopolymerization initiators exemplified later in the item "Cholesteric
Liquid Crystal Film". Also, the hardener is not particularly limited provided that
it causes the reaction of an unsaturated double bond, an epoxy group, or the like
in the thermosetting resin by heating so that they are closs-linked. The examples
of the hardener include acid anhydrides, amines, phenols, imidazoles, dihydrazines,
Lewis acids, Bronsted acid salts, polymercaptans, isocyanates and block isocyanates.
[0058] The content of the fine particles in the at least one high refractive index resin
layer is preferably 40 wt% or more based on the total of the at least one high refractive
index resin layer, more preferably 50 wt% or more, still more preferably 60 wt% or
more, particularly preferably 70 wt% or more, and most preferably 90 wt% or more.
If the content of the fine particles in the at least one high refractive index resin
layer is less than 40 wt%, the refractive index of the resin binder in the at least
one high refractive index resin layer is dominant, thus it is not possible to effectively
reflect the light in the infrared region. The content of the fine particles in the
at least one high refractive index resin layer is preferably 95 wt% or less based
on the total of the at least one high refractive index resin layer. If the content
of the fine particles in the at least one high refractive index resin layer is more
than 95 wt%, the ratio of the resin binder in the at least one high refractive index
resin layer decreases, thus it is difficult to manufacture the infrared shielding
sheet in the shape of a sheet.
[0059] The content of the fine particles in the at least one low refractive index resin
layer is preferably 40 wt% or more based on the total of the at least one low refractive
index resin layer, more preferably 50 wt% or more, still more preferably 60 wt% or
more, particularly preferably 70 wt % or more, and most preferably 90 wt % or more.
If the content of the fine particles in the at least one low refractive index resin
layer is less than 40 wt%, the refractive index of the resin binder in the at least
one low refractive index resin layer is dominant, thus the inrfrared reflecting function
of the infrared shielding sheet is reduced. The content of the fine particles in the
at least one low refractive index resin layer is preferably 95 wt% or less based on
the total of the at least one low refractive index resin layer. If the content of
the fine particles in the at least one low refractive index resin layer is more than
95 wt%, the ratio of the resin binder in the at least one low refractive index resin
layer decreases, thus it is difficult to manufacture the infrared shielding sheet
in the shape of a sheet. Furthermore, if the content of the fine particles in the
at least one low refractive index resin layer is more than 95 wt% under the condition
that the fine particles contained in the at least one low refractive index resin layer
are electrically conductive fine particles, the fine particles are adhered to each
other, which reducing the radio wave transmissibility property of the infrared shielding
sheet.
[0060] The surface resistance of the high refractive index resin layer and the low refractive
index resin layer is preferably 1kΩ/□ (10
3Ω/□) or more, more preferably 10kΩ/□ (10
4Ω/□) or more, still more preferably 1000kΩ/□ (10
6Ω/□) or more. If the surface resistance of the high refractive index resin layer and
the low refractive index resin layer is less than 1kΩ/□, it is undesirable because
the infrared shielding sheet hardly transmits the radio wave.
[0061] The maximum surface height difference (surface roughness) of the at least one high
refractive index resin layer and the at least one low refractive index resin layer
is preferably 70 nm or less, more preferably 60 nm or less, still more preferably
50 nm or less. After dispersing the fine particles in the dispersion liquid until
there is no aggregation of the fine particles, the dispersion liquid is applied (coated)
so as to form the at least one high refractive index resin layer and the at least
one low refractive index resin layer. Thus, it is possible to obtain the desirable
maximum surface height difference of the at least one high refractive index resin
layer and the at least one low refractive index resin layer. If the at least one high
refractive index resin layer and the at least one low refractive index resin layer
have the surface roughness (the maximum surface height difference) of more than 70
nm, the incident infrared light is scattered on the surface of the at least one high
refractive index resin layer and the at least one low refractive index resin layer.
Thus, it is not possible to give a good reflecting function to the infrared shielding
sheet.
[0062] The method for manufacturing the infrared shielding sheet of the present invention
preferably includes the step of forming the high refractive index resin layer and
the low refractive index resin layer by application method. The infrared shielding
sheet of the present invention is preferably manufactured by a method including the
steps of applying and drying application liquid for forming the high refractive index
resin layer and the low refractive index resin layer on the support such as the transparent
support using the applying method appropriately selected from the publicly known applying
methods. The method for applying the application liquid is not particularly limited.
Examples of the method include methods using the following coating apparatuses: bar
coaters such as a wire bar coater; a spin coater; a die coater; a micro gravure coater;
a comma coater; a spray coater; a roll coater; a knife coater and the like. For the
smoothness of the surface of the high refractive index resin layer and the low refractive
index resin layer, the methods using the coating apparatuses suitable for manufacturing
fine films are preferable, the coating apparatuses such as the bar coater, the spin
coater, the die coater and the micro gravure coater.
[0063] Also, the infrared shielding sheet may be formed, according to the intended use,
by laminating at least one function layer such as a cholesteric liquid crystal film,
a birefringence multilayer film, an adhesive layer, and/or a hard coat layer on the
laminated film composed of the high refractive index resin layer and the low refractive
index resin layer (or on the sheet composed of the laminated film and the transparent
support). Furthermore, various additives such as an infrared absorption coloring matter,
an ultraviolet absorbent, an antioxidant and a photostabilizer may be added, as needed,
in the high refractive index resin layer and the low refractive index resin layer,
or in the function layer laminated as necessary.
[0064] In order to block the light in the infrared region that cannot be blocked by the
laminated film composed of the high refractive index resin layer and the low refractive
index resin layer, the infrared shielding sheet may be formed by the laminated film
combined with the publicly known materials such as an infrared absorption coloring
matter, a cholesteric liquid crystal film and a birefringence multilayer film. Preferably,
the infrared absorption coloring matter selectively absorbs the light having the wavelength
from 780 to 2000 nm. Preferably, the cholesteric liquid crystal film selectively reflects
the light having the wavelength from 780 to 2000 nm.
[Infrared Absorption Pigment]
[0065] The infrared absorption coloring matter is not particularly limited. However, in
particular, it is possible to use infrared absorption coloring matters having the
absorption maximum at the wavelength from 750 nm to 1100 nm, for example, a phthalocyanine
coloring matter, an anthraquinone coloring matter, a dithiol coloring matter, a diimmonium
coloring matter, a squarylium coloring matter, a naphthalocyanine coloring matter,
an aminium coloring matter, an organometallic complex coloring matter such as a dithiol
metal complex coloring matter, a cyanine coloring matter, an azo coloring matter,
a polymethine coloring matter, a quinone coloring matter, a diphenylmethane coloring
matter, a triphenylmethane coloring matter and a mercaptonaphthol coloring matter.
[0066] Among the above, at least one of the phthalocyanine coloring matter, the naphthalocyanine
coloring matter, and the anthraquinone coloring matter is suitable for using as the
infrared absorption coloring matter.
[Cholesteric Liquid Crystal Film]
[0067] In the cholesteric liquid crystal film, the molecular axis is aligned in one direction
on one plane, however, the molecular axis is slightly shifted by a certain angle on
a next plane, and further shifted by a certain angle in a further next plane. Thus,
the angle of the molecular axis is successively shifted toward the normal direction
of the plane. Such a structure in which the molecular axis is twisted is called a
chiral structure. It is preferable that the normal (chiral axis) of the plane is substantially
parallel to the thickness direction of the cholesteric liquid crystal film (cholesteric
liquid crystal layer).
[0068] When the light enters the cholesteric liquid crystal film, either of the clockwise
or the counterclockwise circularly polarized light in a specific wavelength region
is reflected. In the chiral structure, when the screw axis indicating the rotation
axis around which is twisted the molecular axis of the liquid crystal compound constituting
the cholesteric liquid crystal film is parallel to the normal of the cholesteric liquid
crystal film, the pitch length p of the chiral structure and the wavelength λ
c of the reflected circularly polarized light satisfy the following relational expressions
(2) and (3):
where λ
c represents the center wavelength in the wavelength region of the light reflected
by the cholesteric liquid crystal film, no represents the refractive index in the
minor axis direction of the molecules of the liquid crystal compound constituting
the cholesteric liquid crystal film, n
e represents the refractive index in the major axis direction of the molecules in the
liquid crystal compound, n represents (no + ne)/2, and θ represents the incident angle
(angle from the normal of the surface) of the light.
[0069] From this, it can be seen that the center wavelength in the wavelength region of
the light reflected by the cholesteric liquid crystal film depends on the pitch length
of the chiral structure in the cholesteric liquid crystal film. Thus, by changing
the pitch length of the chiral structure, it is possible to change the center wavelength
in the wavelength region of the light reflected by the cholesteric liquid crystal
film.
[0070] The number of the layer(s) of the cholesteric liquid crystal film may be one, or
may be more than one. When the cholesteric liquid crystal film has more than one layer,
it is possible to widen the infrared wavelength band that is reflected by the cholesteric
liquid crystal film, thus it is preferable.
[0071] When the cholesteric liquid crystal film has more than one layer, it is preferable
to combine the cholesteric liquid crystal layers that have different twisting directions
of the molecular axis so as to further effectively reflect the light in the center
wavelength region to be reflected. This enables the cholesteric liquid crystal film
to reflect both of the clockwise circularly polarized light and the counterclockwise
circularly polarized light, which realizes the effective reflectance. When it is desired
to widen the wavelength region of the light to be reflected by the cholesteric liquid
crystal film having more than one layer, combination of the cholesteric liquid crystal
layers having different pitch lengths is preferable. Moreover, by combination of the
cholesteric liquid crystal layers having different twisting directions, it is possible
to widen the infrared wavelength region, the light in which is effectively reflected.
As to the number of the layers and the combination of the cholesteric liquid crystal
films for reflecting the clockwise circularly polarized light and for reflecting the
counterclockwise circularly polarized light, it is possible to adopt an appropriate
combination in consideration of the manufacturing cost, the visible light transmittance
and the like.
[0072] As the cholesteric liquid crystal material for forming the cholesteric liquid crystal
film, it is preferable to use a curable liquid crystal composition. Examples of the
liquid crystal composition include at least a rod-like liquid crystal compound, an
optically active compound (chiral compound) and a polymerization initiator. More than
one component may be contained. For example, a polymerizable rod-like liquid crystal
compound and a non-polymerizable rod-like liquid crystal compound may be used in combination.
Also, it is possible to use a low molecular weight rod-like liquid crystal compound
and a high molecular weight rod-like liquid crystal compound in combination. Furthermore,
in order to improve the orientation uniformity, the application suitability and the
film strength, the liquid crystal composition may contain at least one selected from
the various additives such as a horizontal orientation agent, an ununiformity preventive
agent, a cissing preventive agent and a polimerizable monomer (neither the rod-like
liquid crystal compound nor the optically active compound, e.g., a monomer having
a (meth)acrylic group). Also, it is possible to add to the liquid crystal composition,
as needed, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a
photostabilizer, a coloring material, a metal oxide fine particles and the like to
the extent that the optical performance is not degraded.
(1) Rod-like Liquid Crystal Compound
[0073] As the rod-like liquid crystal compound, a rod-like nematic liquid crystal compound
is preferable. Suitable examples of the rod-like nematic liquid crystal compound include
the low molecular weight liquid crystal compounds and the high molecular weight liquid
crystal compounds such as azomethines, azoxys, cyanobiphenyls, cyanophenylesters,
benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes,
cyano-substituted phenylpyrimidines, phenyldioxanes, tolans and alkenylcyclohexylbenzonitriles.
[0075] The polymerizable rod-like liquid crystal compound can be obtained by introducing
a polymerizable group to the rod-like liquid crystal compound. Examples of the polymerizable
group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl
group. As the polymerizable group, the unsaturated polymerizable group is preferable,
an ethylenically unsaturated polymerizable group is more preferable. The polymerizable
groups can be introduced in molecules of the rod-like liquid crystal compound using
various methods. The number of the polymerizable group that the polymerizable rod-like
liquid crystal compound has is preferably 1 to 6, more preferably 1 to 3. Examples
of the polymerizable rod-like liquid crystal compound include the compounds described,
for example, in:
Makromol. Chem., volume 190, p. 2255 (1989);
Advanced Materials, volume 5, p. 107 (1993);
US 4,683,327;
US 5,622,648;
US 5,770,107;
WO 95/22586;
WO 95/24455,
WO 97/00600;
WO 98/23580;
WO 98/52905;
JP H01-272551 A;
JP H06-016616 A:
JP H07-110469 A;
JP H11-080081; and
JP 2001-328973 A. It is possible to use two or more polymerizable rod-like liquid crystal compounds
in combination. By using two or more polymerizable rod-like liquid crystal compounds
in combination, the orientation temperature can be reduced.
(2) Optically Active Compound (Chiral Agent)
[0076] The liquid crystal composition exhibits the cholesteric liquid crystal phase, thus,
preferably it contains an optically active compound. However, if the molecules of
the rod-like liquid crystal compound have asymmetric carbon atoms, the cholesteric
liquid crystal film can be stably formed in some circumstances, without addition of
the optically active compound. As the optically active compound, it is possible to
select from the various publicly known chiral agents (for example, described in
EKISHO DEBAISU HAND BOOK, chapter 3, item 4-3, TN, STN Chiral Agent, p. 199, JAPAN
SOCIETY FOR THE PROMOTION OF SCIENCE, 142th committee, 1989). Generally, the optically active compound includes asymmetric carbon atoms. However,
it is also possible to use, as the chiral agent, an axially chiral compound or a planar
chiral compound not including the asymmetric carbon atom. Examples of the axially
chiral compound or a planar chiral compound include binaphthyl, helicene, paracyclophane
and derivatives thereof. The optically active compound (chiral agent) may have a polymerizable
group. When the optically active compound has a polymerizable group (i.e., the polymerizable
optically active compound) and the rod-like liquid crystal compound used in combination
therewith also has a polymerizable group (i.e., the polymerizable rod-like liquid
crystal compound), due to a polymerization reaction of the polymerizable optically
active compound and the polymerizable rod-like liquid crystal compound, it is possible
to form a polymer having a repeating unit derived from the rod-like liquid crystal
compound and a repeating unit derived from the optically active compound. In this
aspect, the polymerizable group that the polymerizable optically active compound has
is preferably the same kind as the polymerizable group that the polymerizable rod-like
liquid crystal compound has. Therefore, the polymerizable group of the optically active
compound is preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl
group, and more preferably, an unsaturated polymerizable group, and still more preferably
an ethylenically unsaturated polymerizable group. Also, the optically active compound
may be a liquid crystal compound.
[0077] The amount of the optically active compound in the liquid crystal composition is
preferably 0.1 to 30 parts by mol to 100 parts by mol of the liquid crystal compound
used therewith. Reduction in the amount of the optically active compound to be used
is preferable, which is likely to not affect the liquid crystal property of the liquid
crystal composition. Therefore, the optically active compound to be used as the chiral
agent is preferably a compound having a strong torsion so that the small amount thereof
can achieve a desirable twisting orientation of the helical pitch. Such a chiral agent
having a strong torsion is, for example, described in Patent Document
JP 2003-287623 A, which can be suitable for use.
(3) Polymerization Initiator
[0078] The liquid crystal composition used for forming the cholesteric liquid crystal film
(a light reflecting layer) is preferably a polymerizable liquid crystal composition,
accordingly, it is preferable to contain a polymerization initiator. In case of progressing
the curing reaction of the polymerizable liquid crystal composition by ultraviolet
irradiation, the polymerization initiator to be used is preferably a photopolymerization
initiator capable of starting the polymerization reaction by the ultraviolet irradiation.
The above photopolymerization initiator is not particularly limited. Examples of the
photopolymerization initiator include:
2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one ("IRGACURE® 907" manufactured
by BASF Japan Ltd.); 1-hydroxycyclohexyl phenyl ketone ("IRGACURE® 184" manufactured
by BASF Japan Ltd.); 4-(2-hydroxyethoxy)phenyl 2-hydroxy-2-propyl ketone ("IRGACURE®
2959" manufactured by BASF Japan Ltd.); 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one
("DAROCUR® 953" manufactured by Merck KGaA); 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one
("DAROCUR® 1116" manufactured by Merck KGaA); 2-hydroxy-2-methyl-1-phenylpropan-1-one
("IRGACURE® 1173" manufactured by BASF Japan Ltd.); acetophenone compounds such as
diethoxyacetophenone, benzoin compounds such as benzoin, benzoin methyl ether, benzoin
ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and 2,2-dimethoxy-2-phenylacetophenone
("IRGACURE® 651" manufactured by BASF Japan Ltd.); benzophenone compounds such as
benzoylbenzoic acid, methyl o-benzoylbenzonate, 4-phenylbenzophenone, hydroxybenzophenone,
4-benzoyl-4'-methyldiphenylsulfide and 3,3'-dimethyl-4-methoxybenzophenone ("KAYACURE®
MBP" manufactured by Nippon Kayaku Co., Ltd.);
thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone ("KAYACURE® CTX"
manufactured by Nippon Kayaku Co., Ltd.), 2-methylthioxanthone, 2,4-dimethylthioxanthone
("KAYACURE® RTX" manufactured by Nippon Kayaku Co., Ltd.), isopropylthioxanthone,
2,4-dichlorothioxanthone ("KAYACURE® CTX" manufactured by Nippon Kayaku Co., Ltd.),
2,4-diethylthioxanthone ("KAYACURE® DETX" manufactured by Nippon Kayaku Co., Ltd.)
and 2,4-diisopropylthioxanthone ("KAYACURE® DITX" manufactured by Nippon Kayaku Co.,
Ltd.); and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide("LUCIRIN® TPO" manufactured
by BASF Japan Ltd.) The above photopolymerization initiator may be used singularly
or may be used in combination of two kinds or more.
[0079] The content of the photopolymerization initiator in the polymerizable liquid crystal
composition is not particularly limited. However, preferably 0.5 or more parts by
weight of the photopolymerization initiator is contained wih respect to 100 parts
by weight of the total amount of the polymerizable liquid crystal compound and the
polymerizable monomer used as needed. Also, the photopolymerization initiator in the
amount of 10 or less parts by weight is preferable, and in particular, the amount
of 2 or more parts by weight is preferable as well as the amount of 8 or less parts
by weight is preferable.
[0080] When the benzophenone compound or the thioxanthone compound is used as the photopolymerization
initiator, it is preferable to use a reaction auxiliary agent in combination in order
to accelerate the photopolymerization reaction. The reaction auxiliary agent is not
particularly limited. Examples of the reaction auxiliary agent include amine compounds
such as triethanolamine, methyldiethanolamine, triisopropanolamine, n-butylamine,
N-methyldiethanolamine, diethylaminoethyl methacrylate, michler's ketone, 4,4'-bis(diethylamino)benzophenone,
ethyl 4-dimethylaminobenzonate, 2-n-butoxyethyl 4-dimethylaminobenzonate and isoamyl
4-dimethylaminobenzonate.
[0081] The content of the reaction auxiliary agent in the polymerizable liquid crystal composition
is not particularly limited, however, preferably the content is in the range not affecting
the liquid crystal property of the polymerizable liquid crystal composition. Preferably
0.5 or more parts by weight of the reaction auxiliary agent is contained with respect
to 100 parts by weight of the total amount of the polymerizable liquid crystal compound
and the polymerizable monomer used as needed. Also, the reaction auxiliary agent in
the amout of 10 or less parts by weight is preferable, and in particular, the amount
of 2 or more parts by weight is preferable as well as the amount of 8 or less parts
by weight is preferable. Also, the content of the reaction auxiliary agent is preferably
0.5 to 2 times that of the photopolymerization initiator on the weight basis.
[0082] Furthermore, to the polymerizable liquid crystal composition, it is possible to add,
as needed, a leveling agent, a defoamer, an ultraviolet absorber, a light stabilizer,
an antioxidant, a polymerization inhibitor, a cross-linking agent, a plasticizer,
inorganic fine particles, a filler and the like, so that an intended functionality
can be given.
[0083] Examples of the leveling agent include a fluorine compound, a silicon compound, an
acrylic compound and the like. Examples of the defoamer include a silicon defoamer,
a fluorine deformer, a high molecular weight defoamer and the like. Examples of the
ultraviolet absorber include a benzotriazole compound, a benzophenone compound, a
triazine compound and the like. Examples of the light stabilizer include a hindered
amine compound, a benzoate compound and the like. Examples of the antioxidant include
a phenol compound and the like.
[0084] Examples of the polymerization inhibitor include methoquinone, methylhydroquinone,
hydroquinone and the like. Examples of the cross-linking agent include polyisocyanates,
a melamine compound and the like.
[0085] Examples of the plasticizer include phthalic acid ester such as dimethyl phthalate
and diethyl phthalate; trimellitic acid ester such as tris(2-ethylhexyl)trimellitate;
aliphatic dibasic acid ester such as dimethyl adipate and dibutyl adipate; orthophosphoric
acid ester such as tributyl phosphate and triphenyl phosphate; and acetic acid ester
such as glycerin triacetate and 2-ethylhexyl acetate.
[0086] Examples of the inorganic fine particles include: conductive metal oxide fine particles
such as antimony acid zinc fine particles, gallium-doped zinc oxide fine particles,
aluminum-doped zinc oxide fine particles, tin oxide fine particles, antimony-doped
tin oxide fine particles, phosphorus-doped tin oxide fine particles and tin-doped
indium oxide fine particles; and metal oxide fine particles for adjusting the refractive
index such as titanium oxide fine particles and zirconium oxide fine particles. Examples
of the filler include silica particles, acrylic beads, urethane beads and the like,
whose average particle size is in micron order.
[0087] The application method for forming the cholesteric liquid crystal film is not particularly
limited. Examples of the method include methods using the following coating apparatuses:
bar coaters such as a wire bar coater; a spin coater; a die coater; a micro gravure
coater; a comma coater; a spray coater; a roll coater; a knife coater and the like.
For the smoothness of the surface of the cholesteric liquid crystal film, the methods
using the coating apparatuses suitable for manufacturing fine films are preferable,
the coating apparatuses such as the bar coater, the spin coater, the die coater and
the micro gravure coater. Also, in order to further precisely define the orientation
direction of the liquid crystal compound in the cholesteric liquid crystal film, it
is possible to orientate the surface of the base (i.e., the multilayer film, the transparent
support and the like) on which the cholesteric liquid crystal film is formed. For
orientating the surface of the base, the surface of the base is preferably treated
using the rubbing method so as to form an orientated surface.
[Birefringence Multilayer Film]
[0088] The birefringence multilayer film is formed by alternately laminating a layer having
a birefringence (preferably a positive birefringence, hereinafter referred to as the
"birefringence layer") and a layer having an isotropic refringence or a negative birefringence
(hereinafter referred to as the "isotropic refringence layer"). The birefringence
multilayer film is configured based on a coherence interferometry caused by: the difference
in the refractive index between the birefringence layer and the isotropic refringence
layer; and the respective geometric thicknesses. When the refractive index in the
plane surface of the birefringence layer differs from that of the isotropic refringence
layer, the boundary phase of the above two layers forms the reflecting surface.
[0089] The birefringence means that at least two refractive indexes differ from each other
out of the respective refractive indexes of the x axis, the y axis and the z axis
that are orthogonal to each other. When the x axis and the y axis are in the plane
surface of the birefringence layer while the z axis is orthogonal to the plane surface
of the birefringence layer, and furthermore the birefringence layer is constituted
by the orientated polymers, the x axis direction is selected so that it is the direction
having the maximum refractive index in the plane surface, and the x axis direction
corresponds to one of the directions in which the orientated polymers are orientated
(for example, stretched).
[0090] The respective refractive indexes in the plane surface of both the birefringence
layer and the isotropic refringence layer differ depending on the layers (i.e., n
1x ≠ n
2x and n
1y n
2y, where n
1x and n
1y represent the respective refractive indexes in the plane surface of the birefringence
layer in the x axis direction and the y axis direction, and n
2x and n
2y represent the respective refractive indexes in the plane surface of the isotropic
refringence layer in the x axis direction and the y axis direction). It is preferable
that the respective refractive indexes of the birefringence layer and the isotropic
refringence layer in the z axis direction are equal to each other, which results in
the uniform reflectance over the visual angle range since the reflection of the p-polarized
light does not depend on the incidence angle of the light.
[0091] In order to increase the refractive index in the plane surface of the birefringence
layer, it is possible to increase the difference in the refractive index between the
birefringence layer and the isotropic refringence layer by using a birefringence polymer
(preferably a birefringence polymer having a positive birefringence) for the birefringence
layer, the birefringence polymer being at least uniaxially orientated, or preferably,
biaxially orientated.
[0092] The respective optical thicknesses of the birefringence layer and the isotropic refringence
layer are controlled to be λ
c/4, where λc represents the center wavelength of the wavelength region of the light
reflected by the above layers. Alternatively, the birefringence layer may have the
different optical thickness from that of the isotropic refringence layer to the extent
that the optical thicknesses of the birefringence layer and the isotropic refringence
layer total λ
c/2 (or a multiple number of λ
c). To constitute the birefringence layer, a material orientated (to have the positive
birefringence) by being stretched is used. For example, PEN (polyethylene naphthalate),
PET and the like are used. To constitute the isotropic refringence layer, a material
not orientated (or orientated to have the negative birefringence) by being stretched
is used. For example, PMMA (polymethyl methacrylate) and the like are used. Also,
a material for the birefringence multilayer structure can be manufactured by forming
the multilayer film to be stretched using, for example, the simultaneous co-extrusion
method described in Patent Document
JP 2008-528313 T. Since the difference in the refractive index between the birefringence layer and
the isotropic refringence layer is small, it is preferable to laminate many birefringence
layers and isotropic refringence layers. It is preferable that the number of the laminated
layers (the total of the layers) of the birefringence layers and the isotropic refringence
layers is in the range from 3 or more to 1000 or less, in consideration of the desirable
wavelength region to be reflected, the manufacturing cost and the like.
[Interlayer Film for Laminated Glass]
[0093] The interlayer film for laminated glass of the present invention is characterized
in comprising: the infrared shielding sheet of the present invention; and an interlayer
film that is formed on at least one of outermost layers of the infrared shielding
sheet. The interlayer film for laminated glass of the present invention preferably
includes a first interlayer film and a second interlayer film formed on the respective
outermost layers of both sides of the infrared shielding sheet of the present invention
so as to easily form the laminated glass.
[0094] The interlayer film for laminated glass of the present invention preferably includes
the second interlayer film in addition to the first interlayer film. In the normal
interlayer film for laminated glass, the respective thicknesses of the first interlayer
film and the second interlayer film of both sides of the infrared shielding sheet
are the same. However, the present invention is not limited to the above aspect of
the interlayer film for laminated glass. In the interlayer film for laminated glass
of the present invention, the thickness of the first interlayer film may be different
from the thickness of the second interlayer film. Also, the composition of the first
interlayer film may be the same as or different from the composition of the second
interlayer film.
[0095] The heat shrinkage before and after the step thermocompressively bonding the interlayer
film for laminated glass including the first and the second interlayer films is preferably
1 to 20% in the range of heating temperature at the time, more preferably 2 to 15%,
in particular, 2 to 10%. The first and the second interlayer films preferably have
the respective thicknesses of 100 to 1000 µm, more preferably of 200 to 800 µm, still
more preferably of 300 to 500 µm. Also, the first and second interlayer films may
be thickened by laminating multiple sheets.
[0096] As the standard brittleness of the first and second interlayer films, the breaking
elongation by the tension test is preferably 100 to 800%, more preferably, 100 to
600%, still more preferably 200 to 500%.
[0097] The interlayer film preferably contains polyvinyl butyral. The first and the second
interlayer films are preferably resin interlayer films. The resin interlayer film
is preferably a polyvinyl acetal resin film containing polyvinyl acetals as the main
component. The polyvinyl acetal resin film is not particularly limited. For example,
those described in Patent Documents
JP H06-000926 A and
JP 2007-008797 A may be preferably used. Among the polyvinyl acetal resin films, a polyvinyl butyral
resin film (polyvinyl butyral film) is preferably used in the present invention. The
polyvinyl butyral resin film is not particularly specified provided that it is a resin
film containing polyvinyl butyral as the main component, and the polyvinyl butyral
resin films widely used in the publicly known interlayer film for laminated glass
may be adopted. Above all, in the present invention, the interlayer film is preferably
a resin interlayer film containing polyvinyl butyral or ethylene vinyl acetate as
the main component, and more preferably, is the resin interlayer film containing polyvinyl
butyral as the main component. Note that the resin as the main component means a resin
whose ratio in the resin interlayer film is 50 wt% or more.
[0098] The first and second interlayer films may contain an additive to the extent of not
departing from the spirit and scope of the present invention. Examples of the additive
include heat ray shielding fine particles, sound insulating fine particles and a plasticizer.
Examples of the heat ray shielding fine particles and the sound insulating fine particles
include inorganic fine particles and metallic fine particles. It is possible to obtain
a heat shielding effect by dispersing and mixing the above fine particles in the elastic
body of the first and second interlayer films as the resin interlayer films. At the
same time, it is preferable to prevent sonic wave from propagating with the above
configuration so as to obtain a vibration damping effect. The fine particle preferably
has a spherical shape, however, not necessarily perfectly spherical. Also, the fine
particles may be subjected to deformation. Also, it is preferable that the fine particles
are dispersed in the interlayer film, more preferably, in the interlayer film composed
of polyvinyl butyral (hereinafter referred to as "PVB"). The fine particles may be
appropriately capsulated to add to the interlayer film, or may be added to the interlayer
film along with a dispersant. In the case where the first and second interlayer films
contain the resin component, the amount of the fine particles to be added is not particularly
limited. However, the amount of the fine particles is preferably 0.1 to 10 parts by
weight with respect to 100 parts by weight of the resin component.
[0099] Examples of the inorganic fine particles include calcium carbonate fine particles,
alumina fine particles, kaolin clay, calcium silicate fine particles, magnesium oxide
fine particles, magnesium hydroxide fine particles, aluminum hydroxide fine particles,
magnesium carbonate fine particles, talc powder, feldspar powder, mica powder, barite
powder, barium carbonate fine particles, titanium oxide fine particles, silica fine
particles and glass beads. These may be used individually or used by being mixed.
[0100] Examples of the heat shielding fine particles include tin-doped indium oxide (ITO)
fine particles, antimony-doped tin oxide (ATO) fine particles, aluminum-doped zinc
oxide (AZO) fine particles, indium-doped zinc oxide (IZO) fine particles, tin-doped
zinc oxide fine particles, silicon-doped zinc oxide fine particles, antimonic acid
zinc fine particles, lanthanum haxaboride fine particles, cerium haxaboride fine particles,
gold fine powder, silver fine powder, platinum fine powder, aluminum fine powder,
iron fine powder, nickel fine powder, copper fine powder, stainless fine powder, tin
fine powder, cobalt fine powder and alloy powder containing thereof. Examples of the
light shielding agent include carbon black and red iron oxide. Examples of the pigment
include a mixed pigment having dark reddish brown color made by mixing four kinds
of pigments, i.e., a black pigment carbon black, a red pigment (C.I. Pigment Red),
a blue pigment (C.I. Pigment Blue) and a yellow pigment (C.I. Pigment Yellow).
[0101] The plasticizer is not particularly limited, thus it is possible to use publicly
known plasticizers that are generally used as the plasticizers for this type of interlayer
film. Suitable examples of the plasticizer include triethylene glycoldi(2-ethylbutyrate)
(3GH), triethylene glycoldi(2-ethylhexanoate) (3GO), triethylene glycoldi(n-heptanoate)
(3G7), tetraethylene glycoldi(2-ethylhexanoate) (4GO), tetraethylene glycoldi(n-heptanoate)
(4G7), oligoethylene glycoldi(2-ethylhexanoate) (NGO). When the interlayer film is
the resin interlayer film, the above plasticizer is used generally in the amount from
25 to 70 parts by weight with respect to 100 parts by weight of resin (preferably
polyvinyl acetal resin) being the main component of the resin interlayer film.
[0102] The method for manufacturing the interlayer film for laminated glass of the present
invention preferably includes a step of heat-bonding the interlayer film and the infrared
shielding sheet after laminating the infrared shielding sheet of the present invention
and the interlayer film in order. The method for heat-bonding is not particularly
limited. Thus, it is possible to adopt a thermocompression bonding method in which
a heating body is pressed against the laminated body of the infrared shielding sheet
and the interlayer film (i.e., the infrared shielding sheet on which the interlayer
film is overlapped) and a heat welding method using heating by laser irradiation.
Among the above, as the method for manufacturing the interlayer film for laminated
glass of the present invention, it is preferable that the step of heat-bonding the
infrared shielding sheet to the interlayer film is the step of thermocompressively
bonding the infrared shielding sheet to the interlayer film (i.e., thermocompression
bonding step).
[0103] The step of thermocompression bonding is not particularly limited, however, the method
in which the heating body having the temperature from 80 to 140°C is pressed against
the laminated body of the infrared shielding sheet and the interlayer film is preferable.
The heating body may have a plane surface or a curved surface, or it may be a roller.
For thermocompression bonding, it is possible to use a plurality of heat rollers or
pinching surfaces of the plane surfaces that can be heated, or to use them in combination.
Also, the thermocompression bonding may be performed on both sides or only one side
of the laminated body of the infrared shielding sheet and the interlayer film. In
the latter case, one of the rollers or pinching surfaces for the thermocompression
bonding is not needed to be heated. Among the above, as the method for manufacturing
the interlayer film for laminated glass of the present invention, it is preferable
to use the heat rollers in the thermocompression bonding step, and more preferably,
to use the heated roller and the not-heated roller in combination.
[0104] Generally, the surface of the interlayer film is a rough surface that is treated
by the embossing method and the like so that air can easily escape at the time of
adhesion. Thus, the adhering surface becomes smooth according to the surface to be
adhered so as to have a good optical performance, however, the other surface is needed
to maintain the roughness to be adhered to the glass plate and the like. Therefore,
out of the thermocompression bonding rollers, the roller making contact with the interlayer
film preferably has a rough surface so that the surface roughness of the interlayer
film is maintained. That is, it is preferable that at least one of the both surfaces
of the interlayer film is embossed so that the embossed surface is laminated to make
contact with the infrared shielding sheet of the present invention. Also, after the
thermocompression bonding, the surface of the interlayer film that does not make contact
with the infrared shielding sheet may be aggressively embossed.
[0105] The transparent support that is used for preparation of the infrared shielding sheet
may be exfoliated before or after the step of heat-bonding, or may serve as a part
of the interlayer film for laminated glass without exfoliation.
[0106] The method for manufacturing the interlayer film for laminated glass of the present
invention preferably includes a step of laminating the second interlayer film on the
opposite surface of the surface of the infrared shielding sheet on which the first
interlayer film is laminated. That is, the interlayer film for laminated glass of
the present invention preferably has the second interlayer film in addition to the
first interlayer film. As shown in FIG. 5, the interlayer film for glass according
to one aspect of the present invention includes an infrared shielding sheet 2 of the
present invention, a first interlayer film 3 that is formed on one surface of the
infrared shielding sheet 2, and a second interlayer film 3' that is formed on the
other surface of the infrared shielding sheet 2. The infrared shielding sheet 2 and
the second interlayer film 3' may be adjacent to each other, or may include another
component layer therebetween. However, it is preferable that the infrared shielding
sheet 2 and the second interlayer film 3' are adjacent to each other. Also, it is
preferable that the second interlayer film and another component layer are thermocompressively
bonded to the infrared shielding sheet in the same manner as the step of thermocompressively
bonding the first interlayer film to the infrared shielding sheet.
[0107] When processing the interlayer film for laminated glass including the infrared shielding
sheet and the interlayer film, it may be cut by a blade, laser, water jet or heating.
[Laminated Glass]
[0108] The laminated glass of the present invention is characterized in comprising the interlayer
film for laminated glass of the present invention and a plurality of glass plates
(e.g. two glass plates), in which the interlayer film for laminated glass is interposed
between the plurality of glass plates (at least two glass plates). The laminated glass
of the present invention may be appropriately cut to have a desired size.
[0109] The intended purpose of the laminated glass of the present invention is not particularly
limited, however, preferably it is used as window glasses of a house or a vehicle.
A window member of the present invention includes the laminated glass of the present
invention.
[0110] The method for laminating the interlayer film for laminated glass with a first glass
plate and a second glass plate is not particularly limited. The interlayer film for
laminated glass may be interposed between the two glass plates using the public known
method so that they are laminated with each other.
[0111] In the configuration of the laminated glass as the laminated body in which the interlayer
film for laminated glass is interposed and held between the two glass plates, the
members are laminated in the following order: the glass plate, the first interlayer
film, the infrared shielding sheet, the second interlayer film and the glass plate.
[0112] FIG. 6 is a schematic view showing one aspect of the configuration of the laminated
glass including the interlayer film for laminated glass interposed and held between
the glass plates according to the present invention. The laminated glass according
to one aspect of the present invention includes: the interlayer film for laminated
glass (i.e., the first interlayer film 3, the infrared shielding sheet 2 and the second
interlayer film 3') as shown in FIG. 5; and a plurality of glass plates 5 and 5'.
The interlayer film for laminated glass is interposed between the plurality of glass
plates 5 and 5' so that the glass plate 5 is adjacent to the first interlayer film
3 and the glass plate 5' is adjacent to the second interlayer film 3'.
[0113] The end edges of the infrared shielding sheet 2 may be inside the end edges of the
glass plates 5 and 5' and the end edges of the first and second interlayer films 3
and 3'. Also, the end edges of the glass plates 5 and 5' and the end edges of the
first and second interlayer films 3 and 3' may be located respectively on the same
positions, or either of the end edges of the glass plates 5 and 5' or the end edges
of the first and second interlayer film 3 and 3' may be protruded.
[0114] As shown in FIG. 6, in the laminated glass in which the interlayer film for glass
(i.e., the laminated body made of the first interlayer film 3, the infrared shielding
sheet 2 and the second interlayer film 3') is interposed and held between the glass
plates 5 and 5', the end edges of the infrared shielding sheet 2 may be located at
the same positions as the respective positions of the end edges of the glass plates
5 and 5' and the end edges of the interlayer films 3 and 3'. Alternatively, in the
laminated glass, the end edges of the infrared shielding sheet 2 may be protruded
from the end edges of the glass plates 5 and 5' and the end edges of the first and
second interlayer films 3 and 3'.
[0115] In the interlayer film for glass (i.e., the laminated body made of the first interlayer
film 3, the infrared shielding sheet 2 and the second interlayer film 3') interposed
and held between the glass plates 5 and 5', the infrared shielding sheet 2 and the
first interlayer film 3 may be adjacent to each other, and the infrared shielding
sheet 2 and the second interlayer film 3' may be adjacent to each other. Alternatively,
another component layer may be interposed between the infrared shielding sheet 2 and
the first interlayer film 3, and between the infrared shielding sheet 2 and the second
interlayer film 3'.
[0116] In the method for manufacturing the laminated glass of the present invention, the
glass plate may be a glass not having the curvature, or may be a curved glass. Also,
the two glass plates that sandwich and hold the interlayer film for laminated glass
may have the different thicknesses, and may be colored. Particularly, when the laminated
glass is used, for example, as a windshield of a vehicle for the purpose of heat insulation,
a colored component as a metal may be mixed in the glass plate within the range in
which the visible light transmittance of the laminated glass is not less than 70%
that is required under JIS R 3211. Generally, the heat insulation property can be
effectively improved by the use of a green colored glass as the glass plate. As to
the color consistency of the green colored glass, it is preferable to adapt the color
consistency to the desired consistency by adjusting the amount of the metal component
to be added or adjusting the thickness of the glass.
[0117] The method for manufacturing the laminated glass of the present invention preferably
includes a step of thermocompressivley bonding the interlayer film for laminated glass
of the present invention that is interposed and held between the glass plates.
[0118] The glass plates and the interlayer film for glass of the present invention that
is interposed and held between the glass plates are compressively bonded preliminarily,
for example, at the temperature of 80 to 120°C during 30 to 60 minutes under the reduced
pressure using a vacuum bag and the like. Then, they are bonded to each other in an
autoclave under the increased pressure of 1.0 to 1.5 MPa at the temperature of 120
to 150°C, thus the laminated glass with the interlayer film for the glass being interposed
between the two glass plates are manufactured.
[0119] After completion of the thermocompression bonding, a cooling manner is not particularly
limited. The laminated glass may be obtained by suitably releasing the pressure while
cooling. In the method for manufacturing the laminated glass of the present invention,
it is preferable to lower the temperature while maintaining the pressure after completion
of the thermocompression bonding in terms of further reducing wrinkles or cracks of
the obtained laminated glass.
[0120] The method for manufacturing the laminated glass of the present invention preferably
includes a step of releasing the pressure successively after lowering the temperature
while maintaining the pressure. Specifically, it is preferable that when the temperature
in the autoclave becomes 40°C or less after lowering the temperature while maintaining
the pressure, then the pressure is released to lower the temperature.
Examples
[0121] Hereinafter, the present invention is further described in details with reference
to the following Examples. In the Examples and Comparative Examples, the term "part(s)"
means "part(s) by weight".
[Example 1]
(Preparation of High Refractive Index Resin Layer A)
[0122] In 4 parts of methyl ethyl ketone (herein after referred to as "MEK") as the solvent,
0.4 part of dipentaerythritol hexaacrylate (trade name: "KAYARAD® DPHA" manufactured
by Nippon Kayaku Co., Ltd., hereinafter simply referred to as "KAYARAD® DPHA") as
the resin binder and 0.05 part of 1-hydroxycyclohexyl phenyl ketone (trade name: "IRGACURE®
184", photopolymerization initiator, manufactured by BASF Japan Ltd., hereinafter
simply referred to as "IRGACURE® 184") were dissolved. In the obtained solution, 4.7
parts of zirconium oxide fine particles (trade name: "NANON5 ZR-010", with the average
primary particle size of 7 to 8 nm, the average dispersed particle size of 15 nm and
the solid component concentration of 30 wt%, manufactured by SOLAR CO., Ltd., dispersion
medium: MEK) were dispersed. Thus, an application liquid A of the high refractive
index resin for forming a high refractive index resin layer A (i.e., dispersion liquid
prepared by dissolving the resin binder and dispersing the fine particles in the solvent)
was prepared.
[0123] Next, the application liquid A of the high refractive index resin was applied on
a PET base material by a wire bar coater. After it was dried for two minutes at 100°C
for evaporating the MEK, the high refractive index resin layer A was prepared by ultraviolet
(hereinafter referred to as "UV") irradiation. The content of the fine particles in
the high refractive index resin layer A was 76 wt% based on the total high refractive
index resin layer A. The respective refractive indexes of the prepared high refractive
index resin layer A at the wavelength of 550 nm and of 1200 nm were measured by a
spectroscopic ellipsometer (trade name: "M-2000", manufactured by J.A. Woollam (Japan)
Co., Inc.) to obtain a value Δn by subtracting the refractive index at the wavelength
of 1200 nm from the refractive index at the wavelength of 550 nm. The surface resistance
of the prepared high refractive index resin layer A was measured by a surface resistance
meter (trade names "Hiresta® UP" and "Loresta® GP", manufactured by Mitsubishi Chemical
Analytech Co., Ltd.).
(Preparation of Low Refractive Index Resin Layer A)
[0124] To 7 parts of toluene as the solvent, the following were added and dispersed: 1.4
parts of tin-doped indium oxide fine particles as non-hollow fine particles (trade
name: "ITO-R", manufactured by CIK Nano Tek Corportion) with the average primary particle
size of 25.6 nm, the powder resistivity of 0.8Ω· cm when compressed at 60 MPa; 0.4
part of KAYARAD® DPHA; 0.05 part of IRGACURE® 184, and 0.3 part of an aminoalkyl methacrylate
copolymer dispersant (trade name: "DISPERBYK®-167", manufactured by BYK Japan KK,
hereinafter occasionally referred to as the "aminoalkyl methacrylate copolymer dispersant").
The dispersion was performed at the peripheral speed of 10m/s using the bead mill.
Thus, an application liquid A of the low refractive index resin for forming a low
refractive index resin layer A (i.e., dispersion liquid prepared by dissolving the
resin binder and dispersing the fine particles in the solvent) was prepared. The tin-doped
indium oxide fine particles had the average dispersed particle size of 40 nm.
[0125] Next, the application liquid A of the low refractive index resin was applied on a
PET base material by the wire bar coater. After it was dried for two minutes at 100°C
for evaporating toluene, the low refractive index resin layer A was prepared by the
UV irradiation. The content of the fine particles in the low refractive index resin
layer A was 65 wt% based on the total low refractive index resin layer A. The respective
refractive indexes of the prepared low refractive index resin layer A at the wavelength
of 550 nm and of 1200 nm were measured by the spectroscopic ellipsometer (trade name:
"M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.) to obtain the value Δn by
subtracting the refractive index at the wavelength of 1200 nm from the refractive
index at the wavelength of 550 nm. The surface resistance of the prepared low refractive
index resin layer A was measured in the same way as the measurement of the surface
resistance of the high refractive index resin layer A.
(Preparation of Laminated Film)
[0126] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of each high refractive index resin layer A at the wavelength of
1200 nm was set to 300 nm, and the optical thickness of each low refractive index
resin layer A at the wavelength of 1200 nm was set to 300 nm. Under the above conditions,
the low refractive index resin layer A and the high refractive index resin layer A
were alternately laminated, in this order (i.e., the order of which the low refractive
index resin layer A makes contact with the PET base material), on the PET base material
as the transparent support having the thickness of 100 µm (trade name: "COSMOSHINE®
A4100", manufactured by Toyobo Co., Ltd., hereinafter occasionally referred to as
"PET base material"). Thus, an infrared shielding sheet according to one example of
the present invention, having 8 layers as the total of the high refractive index resin
layers and the low refractive index resin layers, was prepared. The respective low
refractive index resin layers A were prepared by the method described in the above
(Preparation of Low Refractive Index Resin Layer A), and the respective high refractive
index resin layers A were prepared by the method described in the above (Preparation
of High Refractive Index Resin Layer A).
[Example 2]
(Preparation of High Refractive Index Resin Layer B)
[0127] To 7 parts of toluene, the following were added and dispersed: 1.4 parts of titanium
oxide fine particles (trade name: "TTO-51A", manufactured by ISHIHARA SANGYO KAISHA,
LTD.) with the average primary particle size of 35 nm; 0.4 part of KAYARAD DPHA; 0.05
part of 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one ("IRGACURE® 907"
manufactured by BASF Japan Ltd.); and 0.3 part of a dispersant (trade name: "DISPERBYK®-2001",
manufactured by BYK Japan KK). The dispersion was performed at the peripheral speed
of 10m/s using the bead mill. Thus, an application liquid B of the high refractive
index resin for forming a high refractive index resin layer B was prepared. The titanium
oxide fine particles had the average dispersed particle size of 45 nm.
[0128] Next, the application liquid B of the high refractive index resin was applied on
a PET base material by the wire bar coater. After it was dried for two minutes at
100°C for evaporating toluene, the high refractive index resin layer B was prepared
by the UV irradiation. The content of the fine particles in the high refractive index
resin layer B was 65 wt% based on the total high refractive index resin layer B. The
respective refractive indexes of the prepared high refractive index resin layer B
at the wavelength of 550 nm and of 1200 nm were measured by the spectroscopic ellipsometer
(trade name: "M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.) to obtain the
value Δn by subtracting the refractive index at the wavelength of 1200 nm from the
refractive index at the wavelength of 550 nm. The surface resistance of the prepared
high refractive index resin layer B was measured in the same way as the measurement
of the surface resistance of the high refractive index resin layer A of Example 1.
(Preparation of Laminated Film)
[0129] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of each high refractive index resin layer B at the wavelength of
1200 nm was set to 300 nm, and the optical thickness of each low refractive index
resin layer A at the wavelength of 1200 nm was set to 300 nm. Under the above conditions,
the high refractive index resin layer B and the low refractive index resin layer A
were alternately laminated, in this order (i.e., the order of which the high refractive
index resin layer B makes contact with the PET base material), on the same PET base
material as that used for preparation of the laminated film of Example 1. Thus, an
infrared shielding sheet according to one example of the present invention, having
7 layers as the total of the high refractive index resin layers and the low refractive
index resin layers, was prepared. The respective high refractive index resin layers
B were prepared by the method described in the above (Preparation of High Refractive
Index Resin Layer B) of this Example, and the respective low refractive index resin
layers A were prepared by the method described in the above (Preparation of Low Refractive
Index Resin Layer A) of Example 1.
[Example 3]
(Preparation of High Refractive Index Resin Layer C)
[0130] To 7 parts of toluene, the following were added and dispersed: 1.4 parts of lanthanum
hexaboride fine particles (manufactured by Wako Pure Chemical Industries, Ltd.) with
the average primary particle size of 1 to 2 µm; 0.4 part of KAYARAD® DPHA; 0.05 part
of IRGACURE 184; and 0.3 part of the aminoalkyl methacrylate copolymer dispersant.
The dispersion was performed at the peripheral speed of 10m/s using the bead mill.
The obtained dispersion was subjected to the centrifugal treatment at the rotational
speed of 5000 rpm for 15 minutes using a centrifuge ("Himac® CR18", manufactured by
Hitachi Koki Co., Ltd.). Thus, an application liquid C of the high refractive index
resin for forming a high refractive index resin layer C was prepared. The lanthanum
hexaboride fine particles had the average dispersed particle size of 35 nm.
[0131] Next, the application liquid C of the high refractive index resin was applied on
a PET base material by the wire bar coater. After it was dried for two minutes at
100°C for evaporating toluene, the high refractive index resin layer C was prepared
by the UV irradiation. The content of the fine particles in the high refractive index
resin layer C was 65 wt% based on the total high refractive index resin layer C. The
respective refractive indexes of the prepared high refractive index resin layer C
at the wavelength of 550 nm and of 1200 nm were measured by the spectroscopic ellipsometer
(trade name: "M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.) to obtain the
value Δn by subtracting the refractive index at the wavelength of 1200 nm from the
refractive index at the wavelength of 550 nm. The surface resistance of the prepared
high refractive index resin layer C was measured in the same way as the measurement
of the surface resistance of the high refractive index resin layer A of Example 1.
(Preparation of Laminated Film)
[0132] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of the high refractive index resin layer C at the wavelength of
1200 nm was set to 300 nm, the optical thickness of each high refractive index resin
layer A at the wavelength of 1200 nm was set to 300 nm, and the optical thickness
of each low refractive index resin layer A at the wavelength of 1200 nm was set to
300 nm. Under the above conditions, the high refractive index resin layer C, the low
refractive index resin layer A and the high refractive index resin layer A were laminated,
in the following order: the high refractive index resin layer C; the low refractive
index resin layer A; the high refractive index resin layer A; the low refractive index
resin layer A; and the high refractive index resin layer A (i.e., the order of which
the high refractive index resin layer C makes contact with the PET base material),
on the same PET base material as that used for preparation of the laminated film of
Example 1. Thus, an infrared shielding sheet according to one example of the present
invention, having 5 layers as the total of the high refractive index resin layers
and the low refractive index resin layers, was prepared. The high refractive index
resin layer C was prepared by the method described in the above (Preparation of High
Refractive Index Resin Layer C) of this Example. The respective low refractive index
resin layers A were prepared by the method described in the above (Preparation of
Low Refractive Index Resin Layer A) of Example 1, and the respective high refractive
index resin layers A were prepared by the method described in the above (Preparation
of High Refractive Index Resin Layer A) of Example 1.
[Example 4]
(Preparation of High Refractive Index Resin Layer D)
[0133] A high refractive index resin layer D was prepared in the same way as described in
the above (Preparation of High Refractive Index Resin Layer B) of Example 2 except
that nanodiamonds (diamond fine particles with the average primary particle size of
3.5 nm and the average dispersed particle size of 4.5 nm) were used as the fine particles
in place of the titanium oxide fine particles. The content of the fine particles in
the high refractive index resin layer D was 65 wt% based on the total high refractive
index resin layer D. The respective refractive indexes of the prepared high refractive
index resin layer D at the wavelength of 550 nm and of 1200 nm were measured by the
spectroscopic ellipsometer (trade name: "M-2000", manufactured by J.A. Woollam (Japan)
Co., Inc.) to obtain the value Δn by subtracting the refractive index at the wavelength
of 1200 nm from the refractive index at the wavelength of 550 nm. The surface resistance
of the prepared high refractive index resin layer D was measured in the same way as
the measurement of the surface resistance of the high refractive index resin layer
A of Example 1.
(Preparation of Laminated Film)
[0134] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of each high refractive index resin layer D at the wavelength of
1200 nm was set to 300 nm, and the optical thickness of each low refractive index
resin layer A at the wavelength of 1200 nm was set to 300 nm. Under the above conditions,
the low refractive index resin layer A and the high refractive index resin layer D
were alternately laminated, in this order (i.e., the order of which the low refractive
index resin layer A makes contact with the PET base material), on the same PET base
material as that used for preparation of the laminated film of Example 1. Thus, an
infrared shielding sheet according to one example of the present invention, having
8 layers as the total of the high refractive index resin layers and the low refractive
index resin layers, was prepared. The respective low refractive index resin layers
A were prepared by the method described in the above (Preparation of Low Refractive
Index Resin Layer A) of Example 1, and the respective high refractive index resin
layers D were prepared by the method described in the above (Preparation of High Refractive
Index Resin Layer D) of this Example.
[Example 5]
(Preparation of Low Refractive Index Resin Layer B)
[0135] To the application liquid A of the low refractive index resin prepared by the method
described in the above (Preparation of Low Refractive Index Resin Layer A) of Example
1, 3 parts of hollow silica fine particles (trade name: "THRULYA 1110" with the average
primary particle size of 50 nm and solid content concentration of 20 wt%, manufactured
by JGC Catalysts and Chemicals Ltd., dispersion medium: methyl isobutyl ketone) were
added. Thus, an application liquid B of the low refractive index resin for forming
a low refractive index resin layer B was prepared.
[0136] Next, the application liquid B of the low refractive index resin was applied on a
PET base material by the wire bar coater. After it was dried for two minutes at 100°C
for evaporating toluene and methyl isobutyl ketone, the low refractive index resin
layer B was prepared by the UV irradiation. The content of the fine particles in the
low refractive index resin layer B was 73 wt% based on the total low refractive index
resin layer B. The respective refractive indexes of the prepared low refractive index
resin layer B at the wavelength of 550 nm and of 1200 nm were measured by the spectroscopic
ellipsometer (trade name: "M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.)
to obtain the value Δn by subtracting the refractive index at the wavelength of 1200
nm from the refractive index at the wavelength of 550 nm. The surface resistance of
the prepared low refractive index resin layer B was measured in the same way as the
measurement of the surface resistance of the high refractive index resin layer A of
Example 1.
(Preparation of Laminated Film)
[0137] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of each high refractive index resin layer A at the wavelength of
1200 nm was set to 300 nm, and the optical thickness of each low refractive index
resin layer B at the wavelength of 1200 nm was set to 300 nm. Under the above conditions,
the low refractive index resin layer B and the high refractive index resin layer A
were alternately laminated, in this order (i.e., the order of which the low refractive
index resin layer B makes contact with the PET base material), on the same PET base
material as that used for preparation of the laminated film of Example 1. Thus, an
infrared shielding sheet according to one example of the present invention, having
8 layers as the total of the high refractive index resin layers and the low refractive
index resin layers, was prepared. The respective low refractive index resin layers
B were prepared by the method described in the above (Preparation of Low Refractive
Index Resin Layer B) of this Example, and the respective high refractive index resin
layers A were prepared by the method described in the above (Preparation of High Refractive
Index Resin Layer A) of Example 1.
[Example 6]
(Example of Synthesis of Infrared Absorption Pigment)
[0138] To 120 parts of sulfolane, 15.9 parts of naphtalic anhydride, 29 parts of urea, 0.40
part of ammonium molybdate and 3.5 parts of vanadyl (V) chloride were added. The temperature
of the obtained mixture was increased to 200°C to react the mixture for 11 hours at
the 200°C. After completion of the reaction, the temperature of the mixture after
reaction was decreased to 65°C, then 100 parts of N,N-dimethylformamide (hereinafter
referred to as "DMF") was added so that a solid deposit was filtered and separated.
Thus, the obtained solid was washed by 50 parts of DMF to obtain 20.3 parts of wet
cake. The obtained wet cake was added to 100 parts of DMF, then the temperature of
the mixture was increased to 80°C so as to be stirred for 2 hours at 80°C. The solid
deposit was filtered and separated, then washed by 200 parts of water, thus 18.9 parts
of wet cake was obtained. The obtained wet cake was added to 150 parts of water, then
the temperature of the mixture was increased to 90°C so as to be stirred for 2 hours
at 90°C. The solid deposit was filtered and separated, then washed by 200 parts of
water, thus 16.1 parts of wet cake was obtained. The obtained wet cake was dried at
80°C, thus 12.3 parts of an infrared absorption coloring matter was obtained.
(Preparation of High Refractive Index Resin Layer E)
[0139] The above synthesized infrared absorption coloring matter in an amount of 0.03 parts
was dispersed in the application liquid A of the high refractive index resin that
was prepared by the method described in the above (Preparation of High Refractive
Index Resin Layer A) of Example 1, thus an application liquid E of the high refractive
index resin for forming a high refractive index resin layer E was prepared.
[0140] Next, the application liquid E of the high refractive index resin was applied on
a PET base material by the wire bar coater. After it was dried for two minutes at
100°C for evaporating toluene, the high refractive index resin layer E was prepared
by the UV irradiation. The content of the fine particles in the high refractive index
resin layer E was 76 wt% based on the total high refractive index resin layer E. The
respective refractive indexes of the prepared high refractive index resin layer E
at the wavelength of 550 nm and of 1200 nm were measured by the spectroscopic ellipsometer
(trade name: "M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.) to obtain the
value Δn by subtracting the refractive index at the wavelength of 1200 nm from the
refractive index at the wavelength of 550 nm. The surface resistance of the prepared
high refractive index resin layer E was measured in the same way as the measurement
of the surface resistance of the high refractive index resin layer A of Example 1.
(Preparation of Low Refractive Index Resin Layer C)
[0141] The above synthesized infrared absorption coloring matter in an amount of 0.03 parts
was dispersed in the application liquid A of the low refractive index resin that was
prepared by the method described in the above (Preparation of Low Refractive Index
Resin Layer A) of Example 1, thus an application liquid C of the low refractive index
resin for forming a low refractive index resin layer C was prepared.
[0142] Next, the application liquid C of the low refractive index resin was applied on a
PET base material by the wire bar coater. After it was dried for two minutes at 100°C
for evaporating toluene, the low refractive index resin layer C was prepared by the
UV irradiation. The content of the fine particles in the low refractive index resin
layer C was 66 wt% based on the total low refractive index resin layer C. The respective
refractive indexes of the prepared low refractive index resin layer C at the wavelength
of 550 nm and of 1200 nm were measured by the spectroscopic ellipsometer (trade name:
"M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.) to obtain the value Δn by
subtracting the refractive index at the wavelength of 1200 nm from the refractive
index at the wavelength of 550 nm. The surface resistance of the prepared low refractive
index resin layer C was measured in the same way as the measurement of the surface
resistance of the high refractive index resin layer A of Example 1.
(Preparation of Laminated Film)
[0143] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of each high refractive index resin layer E at the wavelength of
1200 nm was set to 300 nm, and the optical thickness of each low refractive index
resin layer C at the wavelength of 1200 nm was set to 300 nm. Under the above conditions,
the low refractive index resin layer C and the high refractive index resin layer E
were alternately laminated, in this order (i.e., the order of which the low refractive
index resin layer C makes contact with the PET base material), on the same PET base
material as that used for preparation of the laminated film of Example 1. Thus, an
infrared shielding sheet according to one example of the present invention, having
8 layers as the total of the high refractive index resin layers and the low refractive
index resin layers, was prepared. The respective low refractive index resin layers
C were prepared by the method described in the above (Preparation of Low Refractive
Index Resin Layer C) of this Example, and the respective high refractive index resin
layers E were prepared by the method described in the above (Preparation of High Refractive
Index Resin Layer E) of this Example.
[Example 7]
(Preparation of Cholesteric Liquid Crystal Film)
[0144] To 26 parts of cyclopentanone, the following were added: 10 parts of LC-242 (rod-like
liquid crystal compound, manufactured by BASF Japan Ltd); 0.25 part of LC-756 (chiral
agent, manufactured by BASF Japan Ltd); and 0.5 part of 2,4,6-trimethylbenzoyldiphenylphosphine
oxide (trade name "LUCIRIN® TPO", polymerization initiator, manufactured by BASF Japan
Ltd). Thus, an application liquid A of the liquid crystal was prepared.
[0145] Also, an application liquid B of the liquid crystal was prepared in the same way
as preparation of the application liquid A of the liquid crystal except that the amount
of LC-756 in the application liquid A of the liquid crystal was changed to 0.3 part.
[0146] The application liquid A of the liquid crystal was applied on the same PET base material
as used for preparation of the laminated film of Example 1 by the wire bar coater,
so that the application liquid A of the liquid crystal had the geometric thickness
of 4 µm. After it was dried for two minutes at 130°C for evaporating cyclopentanone,
a first cholesteric liquid crystal film was prepared by the UV irradiation. Furthermore,
the application liquid B of the liquid crystal was applied on the first cholesteric
liquid crystal film by the wire bar coater, so that the application liquid B of the
liquid crystal had the geometric thickness of 4 µm. After it was dried for two minutes
at 130°C for evaporating cyclopentanone, a second cholesteric liquid crystal film
was prepared by the UV irradiation.
[0147] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of each high refractive index resin layer A at the wavelength of
1200 nm was set to 300 nm, and the optical thickness of each low refractive index
resin layer A at the wavelength of 1200 nm was set to 300 nm. Under the above conditions,
the low refractive index resin layer A and the high refractive index resin layer A
were alternately laminated, in this order (i.e., the order of which the low refractive
index resin layer A makes contact with the PET base material), on the cholesteric
liquid crystal film prepared as described above. Thus, an infrared shielding sheet
according to one example of the present invention, having 6 layers as the total of
the high refractive index resin layers and the low refractive index resin layers,
was prepared. The respective low refractive index resin layers A were prepared by
the method described in the above (Preparation of Low Refractive Index Resin Layer
A) of Example 1, and the respective high refractive index resin layers A were prepared
by the method described in the above (Preparation of High Refractive Index Resin Layer
A) of Example 1.
[Example 8]
[0148] An infrared shielding sheet according to one example of the present invention was
prepared in the same way as Example 7 except that a birefringence multilayer film
(trade name: "Nano 90S", manufactured by Sumitomo 3M Ltd.) was used in place of the
two-layerd cholesteric liquid crystal films.
[Example 9]
[0149] To 7 parts of 1-methoxy-2-propanol (hereinafter referred to as "PGM") as the solvent,
the following were added and dispersed: 1.4 parts of tin-doped indium oxide fine particles
as non-hollow fine particles (trade name: "ITO-R", manufactured by CIK Nano Tek Corportion)
with the average primary particle size of 25.6 nm, the powder resistivity of 0.8Ω
· cm when compressed at 60 MPa; 0.04 part of KAYARAD® DPHA; 0.01 part of 2,4,6-trimethylbenzoyl-diphenylphosphine
oxide (trade name "LUCIRIN® TPO", polymerization initiator, manufactured by BASF Japan
Ltd); and 0.06 part of the aminoalkyl methacrylate copolymer dispersant (trade name:
"DISPERBYK®-167", manufactured by BYK Japan KK). The dispersion was performed at the
peripheral speed of 10m/s using the bead mill. Thus, an application liquid D of the
low refractive index resin for forming a low refractive index resin layer D was prepared.
The tin-doped indium oxide fine particles had the average dispersed particle size
of 40 nm.
[0150] Next, the application liquid D of the low refractive index resin was applied on a
PET base material by the wire bar coater. After it was dried for two minutes at 100°C
for evaporating PGM, the low refractive index resin layer D was prepared by the UV
irradiation. The content of the fine particles in the low refractive index resin layer
D was 93 wt% based on the total low refractive index resin layer D. The respective
refractive indexes of the prepared low refractive index resin layer D at the wavelength
of 550 nm and of 1200 nm were measured by the spectroscopic ellipsometer (trade name:
"M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.) to obtain the value Δn by
subtracting the refractive index at the wavelength of 1200 nm from the refractive
index at the wavelength of 550 nm. The surface resistance of the prepared low refractive
index resin layer D was measured in the same way as the measurement of the surface
resistance of the high refractive index resin layer A.
(Preparation of Laminated Film)
[0151] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of each high refractive index resin layer B at the wavelength of
1200 nm was set to 300 nm, and the optical thickness of each low refractive index
resin layer D at the wavelength of 1200 nm was set to 300 nm. Under the above conditions,
the low refractive index resin layer D and the high refractive index resin layer B
were alternately laminated, in this order (i.e., the order of which the low refractive
index resin layer D makes contact with a PET base material), on the PET base material
as the transparent support having the thickness of 100 µm (trade name: "COSMOSHINE®
A4100", manufactured by Toyobo Co., Ltd.). Thus, an infrared shielding sheet according
to one example of the present invention, having 6 layers as the total of the high
refractive index resin layers and the low refractive index resin layers, was prepared.
The respective low refractive index resin layers D were prepared by the method described
in the above (Preparation of Low Refractive Index Resin Layer D), and the respective
high refractive index resin layers B were prepared by the method described in the
above (Preparation of High Refractive Index Resin Layer B) of Example 2.
[Comparative Example 1]
(Preparation of Low Refractive Index Resin Layer E)
[0152] In a solution prepared by solving 1 part of KAYARAD® DPHA and 0.01 part of IRGACURE®
184 in 10 parts of MEK, 3.8 parts of silicon oxide fine particles (trade name: "MEK-ST",
with the average dispersed particle size of 15 nm, manufactured by Nissan Chemical
Industries, Ltd.) were dispersed. Thus, an application liquid E of the low refractive
index resin for forming a low refractive index resin layer E was prepared.
[0153] Next, the application liquid E of the low refractive index resin was applied on a
PET base material by the wire bar coater. After it was dried for two minutes at 100°C
for evaporating MEK, the low refractive index resin layer E was prepared by the UV
irradiation. The respective refractive indexes of the prepared low refractive index
resin layer E at the wavelength of 550 nm and of 1200 nm were measured by the spectroscopic
ellipsometer (trade name: "M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.)
to obtain the value Δn by subtracting the refractive index at the wavelength of 1200
nm from the refractive index at the wavelength of 550 nm. The surface resistance of
the prepared low refractive index resin layer E was measured in the same way as the
measurement of the surface resistance of the high refractive index resin layer A.
(Preparation of Laminated Film)
[0154] The wavelength of the light reflected by the laminated film was set to 1200 nm. The
optical thickness of each high refractive index resin layer A at the wavelength of
1200 nm was set to 300 nm, and the optical thickness of each low refractive index
resin layer E at the wavelength of 1200 nm was set to 300 nm. Under the above conditions,
the high refractive index resin layer A and the low refractive index resin layer E
were alternately laminated, in this order (i.e., the order of which the high refractive
index resin layer A makes contact with the PET base material), on the same PET base
material as that used for preparation of the laminated film of Example 1. Thus, an
infrared shielding sheet as a comparative example, having 7 layers as the total of
the high refractive index resin layers A and the low refractive index resin layers
E, was prepared. The respective high refractive index resin layers A were prepared
by the method described in the above (Preparation of High Refractive Index Resin Layer
A) of Example 1.
[0155] The visible light transmittance, the haze and the total solar transmittance (Tts)
of the respective infrared shielding sheets of Examples 1 to 9 and Comparative Example
1 were measured by the methods described below.
(Measurement of Visible Light Transmittance of Infrared Shielding Sheet)
[0156] The visible light transmittance of each of the obtained infrared shielding sheets
at the wavelengths from 380 to 780 nm was measured in conformity to JIS R 3106 using
a spectrophotometer (trade name: "UV-3100" manufactured by SHIMADZU CORPORATION).
(Measurement of Total Solar Transmittance (Tts) of Infrared Shielding Sheet)
[0157] The total solar transmittance (Tts) is a scale for indicating how much energy of
the thermal energy from the sun (total solar energy) transmits the material as the
measurement object. The total solar transmittance (Tts) of the infrared shielding
sheet was calculated by the measurement method and the calculation formula defined
by ISO 13837. As the calculated value of the total solar transmittance of the infrared
shielding sheet is decreased, the total solar energy transmitting the infrared shielding
sheet is decreased, which indicates the high heat-ray shielding property of the infrared
shielding sheet.
(Measurement of Haze of Infrared Shielding Sheet)
[0158] The haze of each of the obtained infrared shielding sheets was measured in conformity
to JIS K 6714 using a haze meter (trade name: "TC-H III DPK" manufactured by Tokyo
Denshoku Co., Ltd.).
[0159] Table 1 below indicates the following measurement results of the infrared shielding
sheets of Examples 1 to 9 and Comparative Example 1: the visible light transmittance;
the haze, the total solar transmittance; the respective refractive indexes (each referred
to as "n (550 nm)" in the Table) of the high refractive index resin layer (referred
to as "high refractive layer" in the Table) and the low refractive index resin layer
(referred to as "low refractive layer" in the Table) respectively at the wavelength
of 550 nm; the respective refractive indexes (each referred to as "n (1200 nm)" in
the Table) of the above resin layers respectively at the wavelength of 1200 nm; the
value Δn obtained by subtracting the refractive index at the wavelength of 1200 nm
from the refractive index at the wavelength of 550 nm; and the surface resistance.
Note that in the case where the infrared shielding sheet contains a plurality kinds
of high refractive index resin layers, the properties (the refractive index, the value
Δn obtained by subtracting the refractive index at the wavelength of 1200 nm from
the refractive index at the wavelength of 550 nm, and the surface resistance) of only
the high refractive index resin layer making contact with the PET base material are
indicated in Table 1.
Table 1
|
Visible Light Transmittance |
Haze |
Tts |
High Refractive Layer n(550nm) |
High Refractive Layer Δn |
High Refractive Layer Surface Resistance |
Low Refractive Layer n(550nm) |
Low Refractive Layer Δn |
Low Refractive Layer Surface Resistance |
High Refractive Layer n(1200nm) |
Low Refractive Layer n(1200nm) |
Example 1 |
87.10% |
0.4% |
72.70% |
1.75 |
0.03 |
1×1013Ω/□ |
1.64 |
0.31 |
1×107Ω/□ |
1.72 |
1.33 |
Example 2 |
82.70% |
0.4% |
69.70% |
1.88 |
0.05 |
1×1013Ω/□ |
1.64 |
0.31 |
1×107Ω/□ |
1.83 |
1.33 |
Example 3 |
77.90% |
0.5% |
63.60% |
1.62 |
-0.28 |
1×1010Ω/□ |
1.64 |
0.31 |
1×107Ω/□ |
1.90 |
1.33 |
Example 4 |
86.50% |
0.4% |
71.50% |
1.70 |
0.02 |
1×1010Ω/□ |
1.64 |
0.31 |
1×107Ω/□ |
1.68 |
1.33 |
Example 5 |
87.00% |
0.4% |
70.00% |
1.75 |
0.03 |
1×1013Ω/□ |
1.58 |
0.28 |
1×1010Ω/□ |
1.72 |
1.30 |
Example 6 |
79.30% |
04% |
58.30% |
1.75 |
0.03 |
1×1013Ω/□ |
1.64 |
0.31 |
1×107Ω/□ |
1.72 |
1.33 |
Example 7 |
85.00% |
0.4% |
66.20% |
1.75 |
0.03 |
1×1013Ω/□ |
1.64 |
0.31 |
1×107Ω/□ |
1.72 |
1.33 |
Example 8 |
82.20% |
0.5% |
50.90% |
1.75 |
0.03 |
1×1013Ω/□ |
1.64 |
0.31 |
1×107Ω/□ |
1.72 |
1.33 |
Example 9 |
83.9% |
0.3% |
65.7% |
1.88 |
0.05 |
1×1013Ω/□ |
1.66 |
0.46 |
1×1013Ω/□ |
1.83 |
1.15 |
Comparative Example 1 |
90.60% |
0.5% |
84.70% |
1.75 |
0.03 |
1×1013Ω/□ |
1.48 |
0.00 |
1×1013Ω/□ |
1.72 |
1.48 |
[0160] The spectral transmittance and the spectral reflectance of each infrared shielding
sheet of Example 1 and Comparative Example 1 at the wavelengths from 300 to 2500 nm
were measured in conformity to JIS R 3106 using the spectrophotometer (trade name:
"UV-3100" manufactured by SHIMADZU CORPORATION). The measurement results are shown
in FIGS. 1 and 2.
[0161] It can be seen from FIGS. 1 and 2, and Table 1 that the infrared shielding sheet
according to Example 1 of the present invention includes the low refractive index
resin layer having the value of 0.1 or more (specifically, 0.31) obtained by subtracting
the refractive index at an arbitrary wavelength from 780 to 2500 nm (specifically,
at the wavelength of 1200 nm) from the refractive index at the wavelength of 550 nm.
Thus, compared with the infrared shielding sheet of Comparative Example 1 all of whose
low refractive index resin layers have the value less than 0.1 (specifically, 0.00)
obtained by subtracting the refractive index at an arbitrary wavelength from 780 to
2500 nm (specifically, at the wavelength of 1200 nm) from the refractive index at
the wavelength of 550 nm, the infrared shielding sheet according to Example 1 of the
present invention effectively reflects the infrared rays in the wavelength region
from 780 to 1500 nm while absorbing the infrared rays in the wavelength region from
1500 to 2500 nm. Thus, the total solar transmittance (Tts) is remarkably improved.
[0162] In the infrared shielding sheet of Example 2, the layer containing the titanium oxide
fine particles (the high refractive index resin layer B) that is used as each high
refractive index resin layer has the high refractive index at the wavelength in the
infrared region (wavelength of 1200 nm) and has a large difference in the refractive
index between the low refractive index resin layer at the wavelength in the infrared
region, compared with the layer containing the zirconium oxide fine particles (the
high refractive index resin layer A) that is used as each high refractive index resin
layer of the infrared shielding sheet of Example 1. Thus, the infrared shielding sheet
of Example 2 further effectively blocks the infrared rays compared with the infrared
shielding sheet of Example 1 (i.e., the total solar transmittance is improved).
[0163] In the infrared shielding sheet of Example 3, in addition to the infrared absorption
by the lanthanum hexaboride fine particles, the layer containing the lanthanum hexaboride
fine particles that is disposed so as to make contact with the PET base material (i.e.,
the high refractive index resin layer C) has the high refractive index at the wavelength
in the infrared region (wavelength of 1200 nm) and has a large difference in the refractive
index between the low refractive index resin layer at the wavelength in the infrared
region, compared with the layer containing the zirconium oxide fine particles (the
high refractive index resin layer A) that is disposed so as to make contact with the
PET base material in the infrared shielding sheet of Example 1. Thus, the infrared
shielding sheet of Example 3 further effectively blocks the infrared rays compared
with the infrared shielding sheet of Example 1 (i.e., the total solar transmittance
is improved).
[0164] In the infrared shielding sheet of Example 5, the wavelength absorbed by the low
refractive index resin layer containing the tin-doped indium oxide fine particles
(ITO) could be lowered by adding the hollow fine particles to the infrared shielding
sheet of Example 1, almost without changing the refractive index of the infrared rays
by the low refractive index resin layer. Thus, compared with the infrared shielding
sheet of Example 1, the total solar transmittance (Tts) is improved.
[0165] In the infrared shielding sheets of Examples 6 to 8, the laminated film used in the
infrared shielding sheet of Example 1 was combined, respectively, with the infrared
absorption coloring matter, the cholesteric liquid crystal film and the birefringence
multilayer film. This enables these infrared shielding sheets to further effectively
block the infrared rays, while maintaining the visible light transmittance, compared
with the infrared shielding sheet of Example 1 (i.e., the total solar transmittance
was improved).
[0166] In the infrared shielding sheet of Example 9, the content of the fine particles in
the low refractive index resin layer was in the range from 90 to 95 wt% (more specifically,
93 wt%). Thus, the infrared shielding sheet further effectively blocks the infrared
rays, while maintaining the visible light transmittance, compared with the infrared
shielding sheet of Example 2 (i.e., the total solar transmittance is improved).
[0167] As shown in FIG. 2, in the infrared shielding sheet of Comparative Example 1, the
fine particles do not absorb the infrared rays (in the region of the wavelength from
1500 to 2500 nm), thus its total solar transmittance (Tts) is insufficient. Furthermore,
the infrared rays in the region more than 1500 nm (heat-rays), which make human beings
feel sizzling hotness, are not blocked. Therefore, when the infrared shielding sheet
of Comparative Example 1 is laid on window glasses of a house or a vehicle, a person
therein may feel uncomfortable.
[0168] In each infrared shielding sheet of Examples 10 to 15 and Comparative example 2,
the surface resistance and the refractive index according to the wavelength of each
layer (the high refractive index resin layer and the low refractive index resin layer)
of the laminated film were measured as described below.
(Measurement of Surface Resistance of Each Layer)
[0169] Each layer was singularly prepared on the PET base material in the same way as preparation
of each layer (the high refractive index resin layer and the low refractive index
resin layer) of Examples 10 to 15 and Comparative Example 2 so as to obtain each measurement
sample. The surface resistance of each prepared layer was measured by the surface
resistance meter (trade names "Hiresta® UP" and "Loresta® GP", manufactured by Mitsubishi
Chemical Analytech Co., Ltd.).
(Measurement of Refractive Index and Δn of Each Layer)
[0170] Each layer was singularly prepared on the PET base material in the same way as preparation
of each layer (the high refractive index resin layer and the low refractive index
resin layer) of Examples 10 to 15 and Comparative Example 2 so as to obtain each measurement
sample. The respective refractive indexes of the prepared layer at the wavelength
of 550 nm and of 1000 nm were measured by the spectroscopic ellipsometer (trade name:
"M-2000", manufactured by J.A. Woollam (Japan) Co., Inc.) to obtain the value Δn by
subtracting the refractive index at the wavelength of 1000 nm from the refractive
index at the wavelength of 550 nm.
[Example 10]
(Preparation of Application Liquid F of Low Refractive Index Resin)
[0171] In a solution prepared by solving 0.4 part of KAYARAD® DPHA and 0.05 part of IRGACURE®
184 in 4 parts of MEK, 3 parts of hollow silica fine particles (trade name: "THRULYA®
1110" with the average primary particle size of 50 nm and solid content concentration
of 20 wt%, manufactured by JGC Catalysts and Chemicals Ltd., dispersion medium: methyl
isobutyl ketone) were dispersed. Thus, an application liquid F of the low refractive
index resin for forming a low refractive index resin layer F was prepared.
(Preparation of Laminated Film)
[0172] The wavelength of the light reflected by the laminated film was set to 1000 nm. Each
layer was laminated, in the order as shown in Table 2 (note that the number of "Layer"
in Tables 2 to 7 means the number of the location of the layer when the layers are
counted from the far side relative to the PET base material), on the same PET base
material as that used for preparation of the laminated film of Example 1, by applying
the following liquids, diluted as necessary: the application liquid B of the high
refractive index resin prepared in the same way as Example 2; the application liquid
A of the low refractive index resin prepared in the same way as Example 1; and the
application liquid F of the low refractive index resin prepared as described above,
so that each layer has the optical thickness and its coefficient of the QWOT at the
wavelength of 1000 nm as indicated in Table 2. Thus, an infrared shielding sheet according
to one example of the present invention, having 8 layers as the total of the high
refractive index resin layers and the low refractive index resin layers, was prepared.
As to each layer, the application liquid was applied by the wire bar coater so as
to form the resin layer as indicated in the item "Resin Layer" in Table 2. After it
was dried for two minutes at 100°C for evaporating the solvent, each layer was prepared
by the UV irradiation.
[0173] Tables 2 to 7 below indicate the following measurement results of each layer: the
refractive index at the wavelength of 550 nm (referred to as "refractive index n (550
nm)" in the Tables); the refractive index at the wavelength of 1000 nm (referred to
as "refractive index n (1000 nm)" in the Tables); the value Δn obtained by subtracting
the refractive index at the wavelength of 1000 nm from the refractive index at the
wavelength of 550 nm; and the surface resistance.
Table 2
Layer |
Resin Layer |
QWOT |
Optical Thickness |
Refractive Index n (550nm) |
Δn |
Surface Resistance |
Refractive Index n (1000nm) |
1 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
2 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
3 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
4 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
5 |
High Refractive Index Resin Layer B |
2.0 |
500 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
6 |
Low Refractive Index Resin LayerA |
1.0 |
250 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
7 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
8 |
Low Refractive Index Resin Layer A |
2.5 |
625 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
PET Base Material |
|
|
|
|
|
[Example 11]
[0174] The wavelength of the light reflected by the laminated film was set to 1000 nm. An
infrared shielding sheet according to one example of the present invention, having
8 layers as the total of the high refractive index resin layers and the low refractive
index resin layers, was prepared in the same way as Example 10 except that each layer
was laminated so that to have the optical thickness and its coefficient of the QWOT
at the wavelength of 1000 nm as indicated in Table 3.
Table 3
Layer |
Resin Layer |
QWOT |
Optical Thickness |
Refractive Index n (550nm) |
Δn |
Surface Resistance |
Refractive Index n (1000nm) |
1 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
2 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
3 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
4 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
5 |
High Refractive Index Resin Layer B |
1.5 |
375 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
6 |
Low Refractive Index Resin LayerA |
1.5 |
375 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
7 |
High Refractive Index Resin Layer B |
1.2 |
300 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
8 |
Low Refractive Index Resin LayerA |
2.3 |
575 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
PET Base Material |
|
|
|
|
|
[Example 12]
[0175] The wavelength of the light reflected by the laminated film was set to 1000 nm. An
infrared shielding sheet according to one example of the present invention, having
12 layers as the total of the high refractive index resin layers and the low refractive
index resin layers, was prepared in the same way as Example 10 except that: the total
number of the layers obtiained by laminating alternately the high refractive index
resin layer B using the application liquid B of the high refractive index resin and
the low refractive index resin layer F using the application liquid F of the low refractive
index resin was changed from 4 to 6; the total number of the layers obtained by laminating
alternately the high refractive index resin layer B using the application liquid B
of the high refractive index resin and the low refractive index resin layer A using
the application liquid A of the low refractive index resin was changed from 4 to 6;
and each layer was laminated so as to have the opical thickness and its coefficient
of the QWOT at the wavelength of 1000 nm as indicated in Table 4.
Table 4
Layer |
Resin Layer |
QWOT |
Optical Thickness |
Refractive Index n (550nm) |
Δn |
Surface Resistance |
Refractive Index n (1000nm) |
1 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
2 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
3 |
High Refractive Index Resin Layer B |
1.8 |
450 nm. |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
4 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
5 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
6 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
7 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
8 |
Low Refractive Index Resin LayerA |
1.0 |
250 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
9 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
10 |
Low Refractive Index Resin LayerA |
1.0 |
250 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
11 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
12 |
Low Refractive Index Resin LayerA |
2.2 |
550 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
PET Base Material |
|
|
|
|
|
[Example 13]
(Preparation of Low Refractive Index Resin Layer G)
[0176] A dispersion liquid of tin-doped indium oxide fine particles was prepared in the
same way as preparation of the application liquid A of the low refractive index resin
in the above (Preparation of Low Refractive Index Resin Layer A) of Example 1 except
that the amount of the tin-doped indium oxide fine particles was changed to 1.1 parts.
In the prepared dispersion liquid of the tin-doped indium oxide fine particles, 1.5
parts of hollow silica fine particles (trade name: "THRULYA® 1110", with the average
primary particle size of 50 nm and solid content concentration of 20 wt%, manufactured
by JGC Catalysts and Chemicals Ltd., dispersion medium: methyl isobutyl ketone) were
dispersed. Thus, an application liquid G of the low refractive index resin for forming
a low refractive index resin layer G was prepared.
(Preparation of Laminated Film)
[0177] The wavelength of the light reflected by the laminated film was set to 1000 nm. An
infrared shielding sheet according to one example of the present invention, having
6 layers as the total of the high refractive index resin layers and the low refractive
index resin layers, was prepared in the same way as Example 10 except that each layer
was laminated so that: the application liquid used to prepare the layer "4" in Table
2 was changed to the application liquid G of the low refractive index resin; the layers
"7" and "8" in Table 2 were removed; and each layer has the optical thickness and
its coefficient of the QWOT at the wavelength of 1000 nm as indicated in Table 5.
The layer "4" was prepared by: applying the application liquid G of the low refractive
index resin by the wire bar coater; then being dried for two minutes at 100°C for
evaporating the solvent; and being subjected to the UV irradiation.
Table 5
Layer |
Resin Layer |
QWOT |
Optical Thickness |
Refractive Index n (550nm) |
Δn |
Surface Resistance |
Refractive Index n (1000nm) |
1 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
2 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
3 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
4 |
Low Refractive Index Resin Layer G |
2.0 |
500 nm |
1.47 |
0.10 |
1×1012Ω/□ |
1.37 |
5 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
6 |
Low Refractive Index Resin Layer A |
2.5 |
625 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
PET Base Material |
|
|
|
|
|
[Example 14]
(Example of Synthesis of Infrared Absorption Pigment)
[0178] The infrared absorption coloring matter in the amount of 2.3 parts was obtained in
the same way as Example 6.
(Preparation of Infrared Absorption Pigment Layer)
[0179] To 7 parts of toluene, the following were added and dispersed: 0.02 part of the above
synthesized infrared absorption coloring matter; 1 part of KAYARAD® DPHA; 0.05 part
of IRGACURE® 184; and 0.01 part of the aminoalkyl methacrylate copolymer dispersant.
The dispersion was performed at the peripheral speed of 10m/s using the bead mill.
Thus, an application liquid containing the infrared absorption coloring matter for
forming the infrared absorption coloring matter layer was prepared.
[0180] The application liquid containing the infrared absorption coloring matter was applied
on the same PET base material as used for preparation of the laminated film of Example
1 by the wire bar coater, so that the application liquid containing the infrared absorption
coloring matter had the geometric thickness of 4 µm. After it was dried for two minutes
at 100°C for evaporating the solvent, the infrared absorption coloring matter layer
was prepared by the UV irradiation.
(Preparation of Laminated Film)
[0181] An infrared shielding sheet according to one example of the present invention was
prepared by laminating the laminated film on the above prepared infrared absorption
coloring matter layer in the same way as Example 10.
[Example 15]
(Preparation of Cholesteric Liquid Crystal Film)
[0182] The first and second cholesteric liquid crystal layers were prepared, in the same
way as Example 7, on the same PET base material as that used for preparation of the
laminated film of Example 1.
(Preparation of Laminated Film)
[0183] The wavelength of the light reflected by the laminated film was set to 1000 nm. An
infrared shielding sheet according to one example of the present invention, having
6 layers as the total of the high refractive index resin layers and the low refractive
index resin layers, was prepared in the same way as Example 13 except that: each layer
was laminated in the inverse order in the laminated film; and each layer was laminated
on the surface of the PET base material opposite to the surface on which the above
prepared cholesteric liquid crystal layers are laminated, so that each layer has the
optical thickness and its coefficient of the QWOT at the wavelength of 1000 nm as
indicated in Table 6.
Table 6
Layer |
Resin Layer |
QWOT |
Optical Thickness |
Refractive Index n (550nm) |
Δn |
Surface Resistance |
Refractive Index n (1000nm) |
1 |
Low Refractive Index Resin LayerA |
2.0 |
500 nm |
1.64 |
0.24 |
1×107Ω/□ |
1.40 |
2 |
High Refractive Index Resin Layer B |
1.7 |
425 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
3 |
Low Refractive Index Resin Layer G |
1.0 |
250 nm |
1.47 |
0.10 |
1×1012Ω/□ |
1.37 |
4 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
5 |
Low Refractive Index Resin Layer F |
1.0 |
250 nm |
1.37 |
0.00 |
1×1013Ω/□ |
1.37 |
6 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
Base Material |
|
|
|
|
|
Cholesteric Liquid Crystal Layers |
|
|
|
|
|
[Comparative Example 2]
(Preparation of Low Refractive Index Layer)
[0184] The application liquid E of the low refractive index resin was prepared in the same
way as Comparative Example 1.
(Preparation of Laminated Film)
[0185] The wavelength of the light reflected by the laminated film was set to 1000 nm. An
infrared shielding sheet as a comparative example, having 8 layers as the total of
the high refractive index resin layers and the low refractive index resin layers,
was prepared in the same way as Example 10 except that: the application liquids for
forming the layers "2", "4", "6" and "8" of Table 2 were changed to the application
liquid E of the low refractive index resin; and each layer was laminated so as to
have the optical thickness and its coefficient of the QWOT at the wavelength of 1000
nm as indicated in Table 7.
Table 7
Layer |
Resin Layer |
QWOT |
Optical Thickness |
Refractive Index n (550nm) |
Δn |
Surface Resistance |
Refractive Index n (1000nm) |
1 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
2 |
Low Refractive Index Resin Layer E |
1.0 |
250 nm |
1.46 |
0.01 |
1×1013Ω/□ |
1.45 |
3 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
4 |
Low Refractive Index Resin Layer E |
1.0 |
250 nm |
1.46 |
0.01 |
1×1013Ω/□ |
1.45 |
5 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
6 |
Low Refractive Index Resin Layer E |
1.0 |
250 nm |
1.46 |
0.01 |
1×1013Ω/□ |
1.45 |
7 |
High Refractive Index Resin Layer B |
1.0 |
250 nm |
1.88 |
0.05 |
1×1013Ω/□ |
1.83 |
8 |
Low Refractive Index Resin Layer E |
1.0 |
250 nm |
1.46 |
0.01 |
1×1013Ω/□ |
1.45 |
PET Base Material |
|
|
|
|
|
[0186] The visible light transmittance, the haze and the total solar transmittance (Tts)
of the respective infrared shielding sheets of Examples 10 to 15 and Comparative Example
2 were measured as follows.
[0187] The visible light transmittance, the haze and the total solar transmittance of the
respective infrared shielding sheets of Examples 10 to 15 and Comparative Example
2 were measured in the same way as the measurement of the visible light transmittance,
the haze and the total solar transmittance (Tts) of the respective infrared shielding
sheets of Examples 1 to 9 and Comparative Example 1. The measurement results are shown
in the following Table 8.
Table 8
|
Visible Light Transmittance |
Haze |
Tts |
Example 10 |
83.20% |
0.2% |
59.50% |
Example 11 |
84.80% |
0.2% |
61.30% |
Example 12 |
83,40% |
0.3% |
58.20% |
Example 13 |
85.60% |
0.2% |
64.40% |
Example 14 |
70.50% |
0.3% |
48.00% |
Example 15 |
84.40% |
0.2% |
61.10% |
Comparative Example 2 |
90.00% |
0.4% |
78.80% |
[0188] It can be seen from FIGS. 3 and 4, and Table 8 that the infrared shielding sheet
according to Example 10 of the present invention includes the low refractive index
resin layer having the value of 0.1 or more (specifically, 0.24) obtained by subtracting
the refractive index at an arbitrary wavelength from 780 to 2500 nm (specifically,
at the wavelength of 1000 nm) from the refractive index at the wavelength of 550 nm.
Thus, compared with the infrared shielding sheet of Comparative Example 2 all of whose
low refractive index resin layers have the value less than 0.1 (specifically, 0.01)
obtained by subtracting the refractive index at an arbitrary wavelength from 780 to
2500 nm (specifically, at the wavelength of 1000 nm) from the refractive index at
the wavelength of 550 nm, the infrared shielding sheet according to Example 10 of
the present invention effectively reflects the infrared rays in the wavelength region
from 780 to 1500 nm while absorbing the infrared rays in the wavelength region from
1500 to 2500 nm. Thus, the total solar transmittance (Tts) is remarkably improved.
Furthermore, it can be seen from the comparison of FIG. 1 with FIG. 3 that the infrared
shielding sheet according to Example 10 of the present invention includes the layer
having the coefficient of the QWOT of 1.5 or more (2.0 or 2.5) related to the optical
thickness at an arbitrary wavelength from 780 to 2500 nm (specifically, at the wavelength
of 1000 nm). Thus, compared with the infrared shielding sheet of Example 1 all of
whose layers have the coefficient of the QWOT less than 1.5 related to the optical
thickness at an arbitrary wavelength from 780 to 2500 nm (specifically, at the wavelength
of 1000 nm), the infrared shielding sheet according to Example 10 of the present invention
effectively blocks the infrared rays in the wavelength region from 780 to 1500 nm.
[0189] In the infrared shielding sheets of Examples 14 and 15, the laminated film used in
the infrared shielding sheet of Example 1 was combined, respectively, with the infrared
absorption coloring matter or the cholesteric liquid crystal film. This enables these
infrared shielding sheets to further effectively block the infrared rays, while maintaining
the visible light transmittance (i.e., the total solar transmittance is improved).
[0190] As shown in FIG. 4, in the infrared shielding sheet of Comparative Example 2, the
fine particles do not absorb the infrared rays (in the wavelength region from 1500
to 2500 nm), thus its total solar transmittance (Tts) is insufficient. Furthermore,
the infrared rays in the wavelength region more than 1500 nm (heat-rays), which make
human beings feel sizzling hotness, are not blocked. Therefore, when the infrared
shielding sheet of Comparative Example 2 is laid on window glasses of a house or a
vehicle, a person therein may feel uncomfortable.
[Example 16]
(Preparation of Interlayer Film for Laminated Glass)
[0191] A PVB film as the first interlayer film was overlapped with the prepared infrared
shielding sheet of Example 10, thus a laminated body was obtained. The obtained laminated
body was sandwiched and pressed at the position of 1 mm or less from the outer periphery
(four sides) of the infrared shielding sheet by two heat laminating rollers respectively
disposed on the side of the front surface and the side of the rear surface of the
laminated body. Thus, the infrared shielding sheet and the first interlayer film were
thermocompressively bonded. When bonding, the temperature of the heat laminating roller
on the side of the interlayer film was set to 25°C so as to not crush the emboss of
the rear surface of the first interlayer film, while the temperature of the heat laminating
roller on the side of the transparent support (PET base material) was set to 120°C
so as to sufficiently crush the emboss of the surface of the first interlayer film
on the side of the infrared shielding sheet to improve the adhesiveness between the
first interlayer film and the infrared shielding sheet. After that, on the surface
of the infrared shielding sheet opposite to the surface on which was bonded the first
interlayer film, a PVD film as the second interlayer film was laminated, thus, the
interlayer film for laminated glass including the infrared shielding sheet of Example
10 was prepared. Also, five kinds of interlayer films for laminated glass including
respectively the infrared shielding sheets of Examples 11 to 15 were prepared in the
same way as preparation of the above interlayer film for laminated glass except that
the respective infrared shielding sheets of Examples 11 to 15 were used in place of
the infrared shielding sheet of Example 10.
(Finish of Laminated Glass)
[0192] The interlayer film for laminated glass including the above prepared infrared shielding
sheet of Example 10 was laminated so that the lamination was performed in the following
order: the glass plate; the first interlayer film; the infrared shielding sheet; the
second interlayer film; and the glass plate. Thus, the laminated body was prepared,
which has the structure that the two glass plates sandwich and hold the interlayer
film for laminated glass therebetween (i.e., the interlayer film for laminated glass
were interposed between the two glass plates). Here, the respective end edges of the
two glass plates and the respective end edges of the first and second interlayer films
were all located at the same position. The glass plates having the thickness of 2
mm were used. The obtained laminated body having the configuration in which the interlayer
film for laminated glass was interposed between the two glass plates was compressively
bonded preliminarily at 95°C for 30 minutes in the vacuum environment. After preliminary
compression bonding, the laminated body interposed between the two glass plates was
thermocompressively bonded in an autoclave under the pressure of 1.3 MPa at 120°C,
thus the laminated glass was prepared. Also, five kinds of laminated glasses including
respectively the infrared shielding sheets of Examples 11 to 15 were prepared in the
same way as preparation of the above laminated glass except that the respective interlayer
films for laminated glass including the respective infrared shielding sheets of Examples
11 to 15 were used in place of the interlayer film for laminated glass including the
infrared shielding sheet of Example 10.
[0193] The properties of the laminated glasses including the respective infrared shielding
sheets of Examples 10 to 15, all prepared in Example 16, were evaluated. It was confirmed
that the laminated glasses including the respective infrared shielding sheets of Examples
10 to 15 have a good quality without remarkable defects or cords, and serve as a transparent
heat shielding glass having the haze of 0.5% or less.
Industrial Applicability
[0194] According to the present invention, the infrared reflecting function using the difference
in the refractive index is given to the infrared shielding sheet in addition to the
infrared absorbing function of the fine particles. Thus, compared with the conventional
infrared shielding sheet, it is found that the infrared shielding sheet of the present
invention suppresses the increase of the temperature caused by the infrared rays.
Thus, when the infrared shielding sheet of the present invention is laid on window
glasses of a house or a vehicle, it is possible to suppress the increase of the space
temperature inside the house or the vehicle and reduce the load of air conditioning
equipment of the house or the vehicle, which results in energy saving and contribution
to global environment issues. Furthermore, the infrared shielding sheet of the present
invention can selectively block the light in the infrared region, thus it can be used
to a window member of a building or a vehicle, a window glass for a refrigeration/cold
showcase, an IR-cut filter, counterfeit prevention and the like,
Reference Signs List
[0195]
- 1
- Interlayer film for laminated glass
- 2
- Infrared shielding sheet (may including transparent support)
- 3, 3'
- Interlayer film
- 4
- Laminated glass
- 5, 5'
- Glass plate
- 20
- Transparent support
- 21
- High refractive index resin layer
- 22
- Low refractive index resin layer
- 23
- Laminated film
[0196] The present invention may be embodied in other forms without departing from the gist
or essential characteristics thereof. The foregoing examples are therefore to be considered
in all respects as illustrative and not limiting. The scope of the present invention
is indicated by the appended claims rather than by the foregoing description, and
all modifications and changes that come within the meaning and range of equivalency
of the claims are intended to be embraced therein.
[0197] This application claims priority to Japanese Patent Applications No.
2013-104324 filed in Japan on May 16, 2013 and No.
2013-272893 filed in Japan on December 27, 2013, the entire contents of which are hereby incorporated
herein by reference.